.NET Conf 2019 Keynote

hi I'm Scott hunter and I'm here today with my team to announce dotnet core 3 to start off let's talk about what da net is dotnet is this platform we've built for building any kind of application you have whether it's a desktop application a web application cloud mobile gaming IOT AI dotnet is a general-purpose framework for building all of these types of applications I'm super excited to talk about dotnet core and how far it's progressed it's only been out for a few years and we've already grown to over a million active net core developers that it core is our first fully open source dotnet framework and in the short time we've actually been open source we've already taken a hundred thousand PRS so we're building this not just by ourselves but with the community and of course Visual Studio 2019 is the faster the fastest adopted version of Visual Studio ever here's a couple of our customers that we build on top of dotnet we have an awesome page on the dotnet website you can go to to see all of these customers and read the stories behind them so I highly recommend you go and check that out after the conference let's talk about down in core 3 you can actually download this right now you can go to the dotnet website and get it right now the bits are available and it brings a bunch of awesome enhancements to dotnet core first off we brought desktop support for WPF and windows forms any.net core application gets the ability to be fully side-by-side and self-contained meaning dotnet doesn't have to be on the machine we just introduced we're going to introduce a brand new way of building web applications where every web application is a spy' occasion and then of course we're always making you more productive with Visual Studio C sharp and we're gonna talk about a lot of these things today with my team to start off as well Visual Studio 2019 16.3 just shipped as well along with Visual Studio 2019 for Mac 8.3 both of these versions of Visual Studio support dotnet core 3 C sharp 8 they have a ton of productivity improvements performance improvements and if you're a mobile developer they support iOS 13 and Android 10 so they support all the latest stuff bunch of our partners have released brand-new tools today for dotnet core 3 if you're a web developer and you're gonna use blaze or our new spa application there is controls by DevExpress telluric and more that are available today so please try these things out as well so the first thing I want to talk about is micro services micro services is a is a new developer phenomenon it's taken over in the last couple of years when I first arted doing development we build these what we call monolithic app monolithic applications where you build your database and your front-end and your back-end all together in a combined application that was great when we were had small teams building applications but as these applications have gotten bigger and crossed into more spaces it's more important to break them out into smaller pieces so those individual teams can actually work on those pieces so not only can you build micro services but you can also host micro services really really well in kubernetes what kubernetes does for you is it's an Orchestrator and that Orchestrator will basically take your application and manage all the components whether it's configuration whether it's scaling whether it's making sure the application is still running well and we have an awesome one of these called agile kubernetes that runs in our Azure cloud now with dotnet core 3 it's the first version of.net core that really really really enables you to build micro services so what we've done is we've added a bunch of new features one is we have something called G RPC what G RPC is it's a it's a form of communication that gives you strongly typed contracts between the application but what makes it unique is it actually works across all developer technologies we're gonna show it in the context of dotnet and c-sharp today but what's cool is you can actually build a micro service using G RPC and you can call it from Java you can call it from node you can call it from Python any of the languages you want will support this the next thing is worker services while we build great web frameworks the last couple of years as you start thinking about micro services you want these long running applications that handle responses requests in responses and so we now have a first-class template inside of Visual Studio and dotnet core 3 they'll let you build these worker services what's cool about this is you get all the same features you get to configuration that pin Injection all the logging all those things that dotnet core brings or available there as well we're gonna show that a little bit later on and then finally as you abilities api is you want to make sure they're super secure and so what we've done is we've actually worked with one of our partners to make sure that you can actually securely secure your endpoints using identity server and so with that what I'm gonna do next is we're gonna have Glenn Condren come on stage and we're gonna build a dotnet core three micro service and host it up in Azure oh hey Glenn hi how's it going it's going great why don't you switch your machine and let's show us your service yeah so a bit of context for what we're gonna do here is I am gonna build this weather micro services service and then all of my friends after this they're all going to come in and they're gonna consume this thing from an IAS cluster so I am going to encapsulate the logic of going and grabbing the weather data I'm gonna cache it locally make sure we honor expires headers do it's not it's not complicated but it's not trivial so we'll make our own service for it instead of having everybody talk to the weather API themselves so what I have here is I have a just a normal file new G RPC service I have a console app and I have a standard class library we're gonna use later but they're all standard except that in my weather app I have already set up some config for the URI and I've put in some user secrets and stuff so that you know you all don't try and steal all of my tokens so first thing we need is a worker so I am going to add this class we're going to call it weather worker all right and this thing's responsibility is going to be to go and grab the weather data and get it in the cache locally Ram and like this so I have some snippets for pretty much all of my all of my code and so this inherits from background service which we had a little while ago this is how you can add a service that will run forever you know I've got do some logging some config I need config to get my URI and then in kubernetes it actually uses the kubernetes config provider to grab all the secrets from kubernetes secrets which is kind of cool I have a hard-coded location ID because you know you don't need any other weather than that what's in Redmon's and then the mead this execute async method and all its gonna do is loop for as long as the app is going make a HTTP client gonna go and call the weather API get some get some JSON response use the new system text Jason that we added to deserialize that to a type and then cache it and then it's gonna do that every 10 minutes forever for as long as the apps running and so I'm missing this forecast data this is how does the weather endpoint I'm hitting represent the weather and so I'm going to add another class to represent that call a weather model not see us you know if I can not put some some extra caps in so what I did to generate this I have a snippet here for this now what I did to generate this and what you can do is I just grabbed an example Jason payload from the API and I just copied and pasted as c-sharp into visual studio and just made this whole thing for me and I'm just going to ignore it that's a cool feature video convictive take your jason and can convert it to see chart types yeah absolutely it's a super cool feature then okay so now i have a worker this is done i'm good now but except i need to tell the app that it's going to go run that worker service so now over here i'm going to start doing some code I'm gonna add add hosted service which is the name of this feature add weather worker right and then this needed a few things it needed like HTTP and like caching right so services dot add HTTP client so I can inject the HTTP client and then I'm gonna add the memory cache memory cache so that it has a memory cache right this now when I boot this app it's gonna go into every 10 minutes ago and get some more weather data pretty simple pretty cool now I need an endpoint so Scott talked earlier about G RPC and some strongly typed this so so this J PC is a very contract driven approach to our PC so I have a snippet here which gives me this proto file which is the contracts for a G RPC service and so I have this proto file that says I'm gonna make a weather service it's gonna have a get weather streaming endpoint which it should stream weather constantly and it has a get where though that just returns you a single whatever the current weather is and it also defines what the actual response-type is nice thing about making our own like proxy for this where the data is we get to choose the actual surface for our clients and make it relevant and not have too much extraneous data right so if we just call this weather dot proto and then in here the way this actually works is in my CS proj I have this protobuf element which references that way the proto you see the rename worked good job team and it says it's going to generate server because the way that G RPC works is you create a contract and then you generate a lot of code and you just deep lament the bits that matter and you leave all the rest to be generated right I write that contract and I generate either a client or a server using the tools yeah exactly and so then we're gonna go create a weather service now from my from my snippet and so what we have here is a service that implements this weather base and that's that generated code that we just talked about where so we just controlled on my way to glory here I have the base class I have a memory cache because I need to get the data out of the memory cache and then G RPC doesn't want you to have empty method calls but because I'm hard coding the weather for Redmond in this case I've just got this empty type - to fill in for the request type you would probably in most cases have an actual type here that has your data right yeah past your location or something yes I think yeah and then I just have this get current weather response all it does is left hand right hand code to say take that just pasted code the pasted model earlier converted to the one that we want to actually give to all of our all of our friends later and then get where the returns one and then forget where the stream it just loops for as long as the person is connected it just grabs the data out of whatever is in the cache currently and then loops right and then this is to every ten seconds just so that it's easy so you can see something for the sake of the demo we might actually even make this two seconds just so you can see some data constantly changing we know the data will only actually change every ten minutes or so but you want to Keane just can to kind of keep a constant stream happening right and then that's it that's greatest service so if we will rename this to Weather Service so that you know just because we can't have a class with a different file name it'll be terrible and then you know startup CS the way you register these services is we have a map G RPC service endpoint right so now I can change this to Weather Service and that's it at this point my app can run and it'll go do its job and so now you want a client to go grab some of this weather data to test it out so I added this console app earlier conveniently but I also added this weather client Lib so I could go over here to my client console and then add a ref to the proto file and have you generate the client code straight into my console app or any other like dotnet stuff that we're gonna show today but what I can also do is I can come over here I have a completely empty net standard class library except for either default class which I'm going to delete all right and then I can right-click on this and say add service reference and then click add new G RPC service reference browse to the proto file that I had earlier that are the same profile that my weather app is using to generate the server code and then I can say generate client though here in this drop-down right instead of there's some other options for what you can generate I'm generating a client in this case I'm just going okay this is gonna go install the new Yeti goodness that you need to make a Geo PC generate code and generate all the types that you need so this is pretty cool so you built a service if we build our first micro service we install G RPC into that mm-hm and now you want to write a client so all you had to do is basically reference that same proto file from your service in your client and will generate all the code for you absolutely and you just then it generates you kind of the basic yeah it generates you all the codes for the clients class yeah absolutely now all I can do is new it up and start making calls yeah so let's look at what that looks like so I'm just gonna add a normal project reference now to my client class library because everybody can now share this net standard class library that has the client code generated in it all they can choose to reference it directly and then in my program CS I have a have another snippet here where the client alright and I think it's actually the whole the whole class I did this time and then what I'm so yeah you can see here like as you just said this weather client was all generated for me I just I just knew it up I used this channel type to give it the address and then I have a strongly typed method forget whether async which was my contract file you start calling them and start getting results back and write them out to the console absolutely so now I can make ctrl f5 this weather service it'll spin up on my local machine you'll see we'll see the console output in a sec it's gonna see the output go fetch the data and then sit there and be a gr PC endpoint and then so here you can see it going and getting the data and then being ready and then over here I can then like go debug start new instance of my of my client console and my client console a ping up it's gonna grab a single weather and then just say done in this case cuz that's I'm just grabbing is calling a single weather endpoint asynchronously I'm using async like console app that we added a little while ago and then it's like apparently 53 seems reasonable that's pretty awesome so in just a few minutes we built a brand new project using the worker service a long-running process like you would build a micro service yep that goes out and fetches weather from an in point somewhere and then we actually added G RPC to that service so a client can call in to that and get that weather data back yep absolutely well let's switch back to the slides for a second and we'll talk about c-sharp so along with that Nikora 3 we're also shipping the next version of c-sharp c-sharp 8 it has a bunch of new stuff and we kind of broke it down into buckets one that one of the things we think about is we always want to make your code safer to write want to make it easier for you to catch the errors early or prevent the errors from ever occurring and so there's some new features of called nullable and c-sharp 8 to try to address some of that stuff modern as well as we as we look at language we always are looking at other languages and we're looking at the patterns that developers are using today and so one of the cool features we have in c-sharp 8 is async streams and we're gonna show those in a little bit and then productive we always want to make you more productive so the goal of c-sharp is to add the right features and stuff to make it easier for your write code and write code faster with less less text in the screen at the same time also tooling all that with Visual Studio family so you can actually be more productive so what I'm gonna do next I'm gonna bring Mads on and we're gonna take the demo that Glenn had and you know Glenn didn't really write it the best way you could we're gonna we're gonna make it use async streams well I think Glenn did a fantastic job it's just that when he switched back to the last let's switch back to the laptop and look at the the proto that Len put up there there were actually two end points here there was a get whether that he used that he called just before from the client and there's a get whether stream which continues to stream whether down so that's the one we're going to investigate now and find my way back to the program here so there's if you look at the if you look at the client here it also has a get weather stream method so that's probably the one we're going for and that can't be awaited instead we get something that we're gonna explore a little bit so let's just call it response for now and let's start drilling into it so if we say responds dot we see that it has a response stream that sounds stream e let's do that and that one has to read all async that sounds streaming and async that one's pretty good right let's do that one so if I call that then what do I get back that's we can actually drill into that as well let's try to it just f12 our way through there's read all async it returns something called ia singen or mobile of T and Ising enumerable if people remember I know mobile is a core type and I know mobile of T is a core type and net that you can for each and and produce new ones from the language as well with with your return with iterators and so I I think normal is just a it's just an async version of that and we can actually take a very quick look down the rabbit hole here I think a normal ball just like enumerable has a gate enumerator this has to get async enumerator and if we drill into that you can see that it has a current property for the value that we're currently looking at and it has a move next method but this one is async right so if you think about it this is a stream where you can pull elements but every time you pull a new one you do it asynchronously so it might take time and you might you have to wait it okay so that's how that works under the hood now at the language level we would like to support for reaching over these so let's try to for each over there the thing that we got back from our drilling here so let's call that for casts with an s because we hope there are multiple and then we can let's try to for each over its reach VAR forecast in forecast and now what we get is oh this thing can't actually be for each you and that's because in c-sharp we decided you shouldn't just be able to for each over acing things because then you can't look at your code and see and know the racing and know that you're doing something anything right we want every a weight to be visible in the source code so you can know that you're sort of getting off the thread you're doing an icing thing you're it's a point where context might switch and so on so what we have instead is an a weight for each syntax that then you use when you have an eye and eye async enumerable and that you just put the right Curly's in there for for the beauty contest and and we're good so now we've actually called this training in points and now we set it a async loop around that end point yes it the code honestly to me Mads you just took a for each and an edit await in front of it yeah works I tried to make a big deal of it but it's actually pretty amazing I mean yeah it's it's a complicated feature but it looks so simple when you actually use it right and some you know they're more there's more to it you can actually you'll return in an async method as well now returning I think you know mobile so we have you know async you'll return that's pretty useful right amazing and also there's cancellation built in that I kind of skipped over here but that's a little more to it well it's the idea it's it should be simple later today you're gonna have more talks on c-sharp babe we're gonna drill into more and more features than just the async stream that's exactly right yeah so so just after the little after the keynote there'll be two Thaksin perfect thank you let's go back to the slides and we're gonna talk about desktop so today we have still millions of developers building desktop applications you might ask why well because desktop applications are simple to write web applications are hard they require knowing HTML CSS JavaScript and a bunch of stuff desktop applications in dotnet you can just drag some controls to a form write some code they're very quick and simple we've made them much much better in dotnet core three so in.net core three we've brought wind forms in WPF to dotnet core but you get all the benefits of dotnet core so one of those benefits is side by side deployments you no longer have to worry about an update of the framework breaking your application you can even take the app our our the the the framework and compile it directly into a single XE for your application so you just hand that that application to any machine it doesn't even have to have dotnet core on it that's a cool feature in.net core 3 we've made all of the windows 10 api's available to these applications as well so you can call all the things if you want to get bluetooth or something like that you can do that from a win for more WPF application and then finally because it's done at core we do all of it open source and so we've open sourced WinForms and WPF now what I'm gonna do next is talk about App Center this is a new announcement today I'm I'm I started off as a web developer and App Center for desktop applications really excites me because for the first time ever if you're a web developer you can just add some kind of analytics to your website and your to know how many people called it where they're from how long they were on the site wouldn't you want that same information for your desktop applications if you're building a desktop application you likely want to know how many times it's been used or all the features being used and so by adding App Center to your application you get all those benefits absent can also be used to deploy the application including beta versions of the applications to a smaller set of people so super excited to announce that what I'm gonna do next is I'm gonna bring Ali on stage and we're gonna go build a dotnet core 3 desktop application and then we're gonna actually hook it up with App Center so we can get to limit tree on it as well right so let's switch the machine here and a theme we're gonna have today is as we start building applications you know we built that micro service now what you're gonna see us do is basically build more applications on top of that thing showing you can build on it everywhere and share your code right so I happen to have a weather application myself and that's application it's a ving firms app that sits on your desktop and shows you what is the weather right now let me show it to you it's very simple and but it has one problem I haven't actually finished development of that app I put together UI I put some dummy data that shows the weather on Alderaan planet right now that planet doesn't exist anymore so I all cold yes but I would like to actually show the real data for say Seattle and I just heard that Glen has amazing service running in kubernetes and he also has a client library that I can just use in my fin from supplication to that right and not only that we can actually use it from any dotnet application right mobile web WPF so let's take a look at the library that Glenn created for us if I right click on properties I can see that this library is targeting dotnet standard 2.1 which is great because that's the latest version of.net standard understand or two point one ships with dotnet core three so it's the it's the latest version under standard that supports dotnet core 3 but it also only runs on done in court three so that probably means yes executive your application a dotnet core three desktop A+ no it's framework because I developed it a while ago where I did not have a choice between core and framework so if we go to properties we can see that my app is targeting dotnet framework four point eight I cannot reference the library right now but what I can do I can port my framework application to dotnet court and then I will be able to use Glenn's library and to do that we created a tool called try convert that will take your dotnet framework project file and it will try to convert it to new SDK style dotnet core project file it's a simple command-line tool I'm gonna type try converting Z and as a parameter I'm going to send the path to my project file and understand for Donnie core the project files are different than they are for done in France and so what we built as we built a global tool that can be installed on a machine it's a sample to help people convert their cs proj from an old-style cs proj to a dotnet course now seus yes exactly and now when i click on properties in my visual studio i can see that now my application is targeting dotnet core 3.1 right so is it in just a few seconds i ported my framework application to.net court so now I can reference the library and to do so I'm gonna right click on dependencies add reference find whether clients sleep click ok and once I did that let's go ahead and update my code that is pulling dummy data at this moment so I have this method pool weather that just gets demo data and I'm not gonna need this code anymore I will also not need they get Diamond data and here I was using the local weather response class but I'm gonna be using the one from the client library so I'm gonna delete that code as well now I will insert a few lines of code I will add users and I will talk to those lines so first thing that I do here I'm creating a client from the library then based on that client I am creating JIRA PC weather forecast service and for this forecast service I'm calling get streaming weather so every time the service on kubernetes is sending out the weather data every two seconds I'm getting the data on my app and let's see how that works so this code looks almost exactly like the same code that cool yes yes exactly second ago what they were calling my name await the same stuff yep so we're showing sharing dotnet code across all my application types and that looks like a real data Seattle 53 degrees and weather doesn't change that often but you can see that I am actually receiving new data every two seconds so once I built the application now I probably want to share it with my friends maybe even community right I'd love to have it have this look at that new feature we talked about single XE that's that's a great idea let's publish it as a single eggsy file and to do that I'm going to go to project file and let me move everything down so it doesn't distract us and I'm gonna insert three lines of code the first line published single file will make package my application and dotnet core in the single is all done it cool all your application is at one single Lexi yeah so nothing has to be on the machine that you give them exactly yes it's completely dependent on from the environment it's going to be running on the cool the second one runtime identifier specifies which platform I exist should target and by default that not quark can run on any platform but if we're publishing it as a single MZ file we need to specify runtime and into fire and the third one is published tree that is a new feature that will trim out all assemblers from your.net core that are not used by your application so that way you don't get the entire dotnet core you get on the assemblies that you need for your app which makes the size much smaller all right once I added that to my project file I'm gonna right click and go publish and publish one more time and while it's publishing we can see that here you can specify the password that symbol exe will be put you can also specify configuration target framework target runtime all those settings can be set from this page as well and it takes a while because right now dreamer feature is working so it's actually analyzing what we can throw away if she goes and looks at your app figures out what the dependencies are is best and it's not perfect we call it experimental disk yes so yeah you might find it actually trims too much stuff out and you have to go back to your CS proj and manually reference to whatever it turned out to hard that is true it will build better tech around this in the future and we'll build better cooling but it is a first step that we wanted to ship and donate core 3 yes and as you said if it trims something out it's very easy to edit back to your project row ok so we published our single egg Z and here it is just one exists that I can send to my friends that they can put out for the community and they will be just able to run it and use the app on any computer that has you doesn't even require down in core yes yes so the last thing that I would like to show today is an integration with App Center because as you mentioned web developers have been spoiled for a few years where they could see analytics for their websites they could see how many users they got which devices that what it was accessed from and so on and we would like to enable our desktop developers with the same features so for that you can use App Center let me go to my epicenter portal it's App Center dot Emma's I created an account and here you can create a new application you can configure it but I already did it for my app it's weather Vin forms up once you do it you will get very detailed instructions on how to add integration with App Center in your program and it's super simple you just add a few new grid packages and then you add a few lines in your project program dot C s file so I will do exactly that I'm gonna first go and add new get packages that are required which are Microsoft App Center analytics and the second one is Microsoft epicenter crashes right once I edit it I'm gonna go to program dot CS file and I will add some museums and this is how I enable epicenter in my lines of code yeah it's basically just one line epicenter that start and I send the key that I get from the console and I specify what I want from my app Center it's analytics and crashes now you can detail crash analytics and you're gonna get monitoring as well letting you know that people actually tried the project exactly and I'm gonna run it but it will take the portal a few seconds so if we go here and we go to analytics you can see some analytics so you can see that I was testing that demoed September 20 and September 23rd just today and you can see a few spikes we will have another demo later today with Danielle and Matt that will go deeper and dive into all details of all the great features that App Center can offer and was that awesome so so to recap what you can do now is you can basically build desktop applications with dotnet core 3 WinForms in WPF you can make them into single legs ease it can easily be distributed you can add rich analytics with Azure wrap Center awesome I'm so so excited about this so let's move back to slides next I want to talk about mobile app design right so xamarin is awesome technology that lets you take all the goodness of nets and make it available to all the mobile devices so the idea here is you can build any iOS and Android app with c-sharp and why would you want to do this where you want to do this because dot Nets got all this rich libraries that you can share across all these applications so for example that micro service that we showed before we probably can share that across Android and iOS that's one of the tenants of dotnet and C sharp and xamarin is being able to actually share the same logic across all your app types Android or iOS another cool part of it is we have a library for building apps called Zen forms basically you build it once and it runs on all the devices and of course also all the xamarin tech is open-source like the rest of dotnet today we have two awesome announcements the first one is sam'l hot reload imagine you're in your application and you're gonna change some of the sam'l files well you don't really want to recompile and republish and wait for all that kind of stuff to happen what you want to do is you want to basically save your sam'l file and have your device refresh immediately even better than that sam'l are xamarin hot restarts which is the ability to also change the source code normally when you change the source code that's a full recompile copy back to the device I wanna be able to change that code and refresh very fast as well and so this one's in private preview today you can go to the URL and sign up and you might get access the hot reload is actually available to download today and so next what I'm gonna do is I'm gonna bring up James and he's gonna show us how to get some xamarin apps Oh awesome Thank You Scout so much I'm here in my way cuz you know I need to get to my Mac get to your man okay awesome well like Scott said I love don''t development with xamarin inside a visual studio what I love is that like Scott said you can share all of your c-sharp and Dada and knowledge across all of your applications and that's what we've done I decided that I wanted to take that weather app import it to iOS and Android and at the same time leverage that same exact 2g RPC logic that olya use and that we're gonna use throughout the rest of the day now two important things to remember like Scott said we have all sorts of different texts of pieces of technology for cross-platform development but with xamarin you have access to a hundred percent of the api's in ios and android and always up-to-date we just shipped iOS 13 and Android 10 support so on top of that we have xamarin forms for cross-platform UI and xamarin essentials for cross-platform native API access so let's go ahead and port that exact same weather application to iOS and Android taking advantage of mobile features so here I am on my Mac which looks the Mac yes there's my Mac boom and of course I need to get started with a great design I'm not a designer Scott sorry but Guzman bar Quinn was nice enough to have this amazing weather application on up labs which is one of my favorite websites to use for mobile and reached out to him super happy that were able to use it and I'm super happy that he's an amazing designer so that's what we're gonna do and I'm over inside a visual studio for Mac we just launched a brand new version with all sorts of new tech so I want to show that off too but where you get started is file new project you have cross-platform apps you have iOS Android dotnet core apps as your functions Mac TV OS and watch OS everything is possible with xamarin and dotnet so what I've done over here is I've added an android and an iOS project and I also have this mobile core it's a dotnet standard library just like we can use to share across all things of dotnet but it has xamarin forms in there and this is my mobile specific code so this is things like my user interface with xamarin forms my models my view models my app state but notice that I have that wider client Lib that olia use that Glen had created so it's inside a visual studio for Mac and I can reuse it right here inside the weather app so that mobile core that's the differentiator for xamarin right that mobile core is the code that is shared across the iOS and Android apps right at once and it gets to be used in all the all the devices you can think of it most of my apps have two different Donna Center libraries one that can be shared with anything so restful service calls models things that are just hey this is Don net code then I have my platform specific code or mobile specific code and this UI runs on iOS and Android right so so for instance here if we take a look at how I built this app is I have a weather page and a weather view model so here up top I have a view model I have a weather client and this G RPC weather forecast service the same exact code that olya was showing earlier and since I'm going to be using sam'l and data binding I have some backing fields so for instance I have a used Celsius a temperature condition time stamp these are things that my user interface is going to display and I can tell it to update via set property but here if we look at this message weather service get streaming weather same code the only difference here is that I'm telling it how to render the user interface so here's a bunch of items I want to display in a list and then I want to update the UI I use Samer and essentials to say begin invoking this logic on the UI thread because that G RPC could be coming in from anywhere right so let me just go ahead and run this really quick so I'm just gonna hit debug this is gonna take my application logic compile up my Android application and then deploy it to an android emulator right here running on my Mac so there we go my application is starting up and what we should see hopefully is a beautiful weather application that I built inside of sam'l alright it's doing some stuff but let's go ahead and fill this in a little bit more so I have my user interface code down here and let's see here I have a pancake view which is a beautiful third-party control that will allow me to do the gradients in the background think I'm missing some stuff okay so I have a label with nothing in it so let's just put in Seattle now I'm going to use that zamel hot real Oh so I'm gonna hit command save it's gonna save that and push the changes over into my device so Seattle right there now what we can also note down here is I'm missing some other things in my UI so for instance here we can go ahead and maybe put in a new column and then I'm gonna say binding and the brand new sam'l intellisense will kick in and I can say temperature there we go now it does look like for some reason my internet has stopped so that's good and I'm getting no updates so things are working exactly as planned because we're doing it all alive just super great but I have zero degrees so it did show up so that's really good alright very cool it's very cold in here yeah so other things that we can do inside of here for instance is like this this Monday here so that's just showing a blank so if I look here on the date what we can see is that I have current weather conditions I have this date property here and maybe I want to change this to a Capitol casing so I can say use a case converter say true hit a save and now that Monday is completely updated 100% now what I'll do because I did change internet right before we're gonna go ahead and stop and redeploy again and bring up a new emulator and see if we can get our internet back on our machine which would be very helpful if so you can see actually how fast the emulator rebooted here so let's go ahead and see if this is gonna spice up for me because having real data would be useful always fun to show the real Mike reserves but you can see how rapidly iterating I was on that user interface using zamel ha reload inside my application so there we go we have lather Oh a cool so one last thing I want to do down here actually two things is I like this collection view which is like all the different humidity UV down here and that's a brand new feature inside of xamarin form so here I can say horizontal or vertical but I'm using a pancake view so I'm gonna add a fancy corner radius here and hit save again again Zam aha reload kicks right in boom I got beautiful rounded so fast so fast but you know I like teardrops which are new hotness I think everyone's gonna pick up boom look at that and I can prove that this is running in real time because down here if I wanted to I could go ahead and say time stamp large and now we can see the time stamp from that gr PC client updating in real time or right there which is super awesome and that's Sam aha reload right there inside a visual studio for Mac with all that gr PC client beautiful user interface boom right there now what I need to do though is also deploy this to iOS so normally I would just say you know set that as my start up project go into my iOS simulator boom did it go but I want to show off some brand new features of hop restart so I'm gonna actually head to my Windows machine right now and do iOS development so let's swap places over here I love this there we go Android on the Mac and iOS on the Windows machine that's correct so I'm right over here now what I want to talk about though is that it is the same projects same solutions that I just had open in Visual Studio for Mac so no matter where you're working you're good to go I know your Mac guy I'm a Windows guy so ideal setup right here so that's gonna make it really easy to go back and forth and again I have my shared code and also that iOS proj and that shared code and everything else that I have in here now what we wanted to do with hot restart is that every once in a while you're changing c-sharp code for a saml hot rila user interface code you need to be able to rapidly iterate on your app but what happens when you want to get it on your device and that's some of the cool tech built into hot restart so what you're able to do and what I have here is my iPhone right here my iPhone 7 that's plugged in to my Windows machine ok and what I have up top is my iPhone right there it's connected it's good to go and what's nice here is that all I have to do is hit debug if you've ever done this before you got to worry about configurations and connections and profiles and certain sand all this stuff but what you're able to do with this technology is restart your application directly on to your device so here for instance I have my device that should be screen mirroring let's go ahead and see if it's gonna cooperate with me let's go ahead and maybe shut it down and reopen it let's do this really quick here there we go and perfect so there's my device I'll put it right over here so there's my device right there on the screen now what's great about this is that I can come into my UI let's go ahead and just make this sticky on top cool that looks good and what I can do is add some new technology into here so for instance maybe I want to convert this into Celsius so again I'll just uncomment some code I have a checkbox I have a label this is data bound to that use Celsius I'm gonna hit save now sam'l ha reload will kick in and notice that it's reloaded I hit a breakpoint I'm debugging my app right here on my device so I can go ahead and continue on good to go all right that's good I must have made some changes to my code that weren't compatible but no worries I can just literally use hot-hot restart here to redeploy again so let's go ahead and deploy there we go and you just saw like I stopped took that took some changes good to go I see you'd back on the phone already and that's back on the phone yeah so this is initializing that debug session and Zam aha Rilla so here's our app here's everything is good and now we have this little back and forth but as you can see Scott or have some issues because I hot reloaded that UI but the temperature is not changing now the background is so my converters my code is running so let's fix this if I go into my view model here we have that temperature property now it's returning temp so that's not good so what I'll do is I'm gonna say use Celsius I full intellisense everything here we're gonna use xamarin essentials what's cool about this is it has a bunch of unit converters built-in so you can do like Hertz 2 degrees Kelvin 2 Celsius here I'm going to say Fahrenheit to Celsius and I'll pass it the temp else just temp there we go make that temp there we go now what we can see is that the UI is telling me that hey I've made c-sharp code changes to my application you need to restart your app and what we can do right here is hit the restart button and this will take all of my code changes that I made redeploy it to my device without having to compile it at all and what's great is that this is literally right to my device in just mere seconds those squiggles go away the application is now back into a debug session that I would expect earlier and what we should hopefully see here once hot reload initialize I can hit Celsius now we're in Celsius and I can use my app my real data use sam'l hot reload for my UI and ha restart when I'm making code changes and play directly to my device and seconds with nothing in between that is amazing I have never seen mobile development on either platform of the on the Mac or Windows deploy 2 devices and restart as fast as I seen with the hot reload and the hot restart yeah this is a game changer we want to focus on developer productivity make sure that our developers building mobile apps with dotnet have the most enjoyable time without anything in between no big set up and boom between those two technology would be hyper productive and share all of your dotnet logic like you've seen before across all the devices all your apps thanks James let's go back to the slides and what we're talking about next is building web applications with blazer so the way I like to think of this is if you're building web applications we've had awesome web frameworks in dotnet for many many years but the web is transition to this new new place where all apps are spa and so what if we could just take the technology we already have the day and say you build any brand new asp.net core blazer application that's an it looks like razor blades your razor and those applications just become spas by default that's what blazer is all about it's full stack web development you build an application in net it's a spy out using the same frameworks and the same technologies you're used to already you don't have to relearn a bunch of new stuff the cool thing about this tech is it also runs in all the browsers so it's compatible with all the browsers that are out there whether it's mobile or desktop and even cooler there's one one final piece which is we have a prototype or in preview thing called web assembly and web assembly lets you take your web application and run it directly on the device that means you don't have to actually that it can be completely disconnected it can be running on a desktop it can be running on a mobile device and running as I like a real desktop application we do that because we can compile your c-sharp directly into web assembly that can run natively in all the browsers so what I'm gonna do next is I'm gonna have Dan Roth come on stage and he's gonna show us how to build a blazer wrap hi Scott core 3 yeah great shall we build a single page web app for our weather application using only net and c-sharp no no JavaScript no JavaScript required alright cool so I'm gonna get close on some of this stuff so I can see my there we go okay so to get started with blazer all you need is not in a course Rio because support for Blazer server apps is now in the box so I'm gonna stop the change this app and I'm gonna open up a new visual studio instance and we'll just go ahead and create our first blazar app so we can just get a feel for how it's done so I'm gonna create a new project and let's create a blazer app there it is right there in the box please drop one sounds like a great name and then for this app I'm gonna pick the Blazer server version we'll talk more about the webassembly version and just a second alright and then we'll go ahead and get this running all right so we can take a quick look at this application in the project and see that there's no there's no JavaScript here right it's just razor files and c-sharp let's go ahead and ctrl f5 so we can see what the application does these razor files the same razor files our developer has been using for the last nine years yeah so these are a combination of HTML and C sharp and it's use of dynamic dynamically render your application so I want to start I'm sorry start without the debugger and let's go ahead and then we'll see what this app does now this will be a simple spa style app like it'll have some interactivity some tabs you can tap around there we go so we have a home page account or fetch data page I can use the back and forward buttons in the browser so I can do client-side routing all those navigations are actually being intercepted in the browser by Blaser and then handled in the browser without the requests ever coming to the server the home page just has a little bit of static HTML nothing too exciting there the counter has this button that if I click the count goes up and there's no page refresh happening there it's all happening that like a client-side app would normally work and then we have fetch data and fetch data is conveniently enough showing a table of weather forecast data now how how is this working how is this possible there's no JavaScript in my project well that's F 12 and look at what is going on in the browser dev tool so I'm gonna refresh so we can see the network traffic and if you look here we can see that there's not much being downloaded it's only about 400 kilobytes of stuff but if we look at the little more carefully we see there's a WebSocket connection being set up between the browser and the server that WebSocket connection is being used to send all the UI events to our components that are running server-side which then executes the components figures out how the UI should be updated and sends the updates back down to the browser to be applied to the actual Dom so that's how it's working and we can we can see that in action let's look at the WebSocket connection a little more closely we'll clear all the messages they've been sent so far and I'm just gonna click you see that see the binary messages flying that's you I events being sent and UI updates being processed that's how that's all it's all happening now let's go look at how that code is actually implemented for that counter component here it is it's a razor syntax a combination of HTML and C sharp we can see it's routable because it has this app page directive at the top to say that the route for this component is slash counter we have some normal HTML markup and then we're using razor syntax to render the value of the current count we also have a button which has an onclick handler normally this would have to be JavaScript but here it's c-sharp we're pointing to a c-sharp method then whenever time the button is clicked the count gets updated the componentry renders and that's how you see those updates on the screen now each of these razor files is actually compiled into a just a normal dotnet class that captures the rendering logic from from the dot razor file and those component classes can be compiled into dotnet assemblies they can be then shared on new Guetta's nougat packages you can build a reusable component library after those component vendors we showed earlier can actually you know have these components we can actually just drop into our apps that's right it makes your life so much more productive you can just grab existing components and go let me show you how that's done how you can build your own component class libraries I'm gonna add a new project to this solution and this time instead of a blazer app I'm gonna pick a razor class library now what is that well a razor class library is actually just a normal dotnet standard class library but it's been set up to also be able to compile dot razor files to compile razor components here we have a razor component that's in the new class library it's pretty simple it's just a div but it does have some styling and this is interesting the the project has this WW root folder with a couple of static files it's kind of styles that CSS it's got a background image that's also used this is a new feature in asp.net core in dotnet course Rio where your class libraries can carry static files that then are made available to the application when the project is referenced or when the new get package is referenced so I'm going to add a reference to that class library like so so I can use that component now to make the these files available in my app I do have to add a link to the styles that I want and we use a simple convention to do that I'm gonna copy this existing link and I'm just going to update it so the convention is its underscore content is the the prefix and then the name of the class library so razor class library 1 and then the path to the file that you want so Styles dot CSS and that's all you got to do now we can use our component in our app so let's just start typing here component 1 I think is the name yep there's intellisense let's close that out we say just go back to the browser you can see that the browser already knows that the app has been changed we just refresh and so we can hopefully see the changes on the home page aha there is our styled component that came from that component class library easy so simple so that's gives us hopefully the basics that's not going to build that weather app I've already started it over here and this solutions we go into the blazer folder I'm gonna set the blazer server version of this app as the startup project there we go now this this blazer app is a little bit interesting in that there's no much in it like it actually doesn't have like hardly any RAZR files in the app project like hardly at all that's because it references this blazer weather core project down below that's a razor class library that contains all the components that's used by the Apple explain why we did that in just a bit but you can look in here and see there's the forecast that razor page and there's all the razor syntax that renders the app let's go ahead and run this let's see what the app looks like this app borrows the same beautiful design that James used for the mobile application there it is so looks pretty good we got the current temperature that's all working now let's look at the code and see how that is done at the top of this page it's got a route just like before it also is injecting an eye weather forecast service that's the same G RPC based service that Jane used using his mobile app same code like so yeah all the code runs everywhere browser mobile desktop anywhere you want and then we've got the razor markup that's just rendering out the the Dom elements for the for the page down below in this code block here's a component life cycle event that fires when the component has rendered and this is kicking off this get weather updates async process which is in this method down here here you see that think for each loop that we saw before who seen before so it's getting the live updates from the server we should be able to see that in the app if I let's zoom in here so 48:45 yeah so that the tics are coming in from the dating all right great now we're missing our ability to actually change the temperature units let's go ahead and fix that I already wrote a little temperature unit picker component it's another dot raiser file in the class library it's just a div let's expand it again it's just a div that has an onclick handler that when it's clicked it will toggle the units from Fahrenheit to Celsius and then it has this parameter temperature unit changed so it can let the parent component know so now we just need to use that so let's go back to our weather forecast page after the temperature let's add the temperature unit picker and we're going to add bind the temperature unit from that component to the temperature unit field in my page and that's all we should need to do I'm gonna control f5 again not control it for you no control it for does I was maybe search or something all right there we go so we're up and running and now we've got this little widget down here by the temperature I can click on it and you can see the temperature automatically updates between Celsius and Fahrenheit now that's a blazer server version of the app but when the cool things about blazer I'm gonna stop you and say we're gonna we're gonna stop on the blazer stuff and we can quickly talk about the webassembly thing so yeah I got you basically webassembly allows you to take these same applications and actually build them where all the code runs on the browser not on the server this is the same app same components it's just instead of running in a blazer server app on the server this is all executing client-side in the browser there's the web assembly file coming down with the app so you can host your app on the server or on the client and take advantage of both sides of the wire cool I am super excited with this blazer stuff this is like you know all my asp.net knowledge now lets me build spy applications without using any JavaScript at all if I want so super cool then full stack web development with dotnet ok let's switch back to the slides real quick when talk about one more big thing machine learning we introduced ml net at Build that's May of this year 1.0 they just shipped and I'm just gonna quickly talk about it and we're gonna bring Bree up and choke a couple demos the whole idea behind ml net is if you're a c-sharp developer you don't want to have to go out and use some other technology or some other language to go and build machine learning into your applications and so you can build ml models and stuff directly in C sharp F sharp without having to go anywhere else we also know that it's hard to actually build you know machine learning models and so we have an awesome preview tool called model builder that you can use to actually just point out some of your data tell it what you want to predict and it'll actually go and write all the code and models for you Bri is going to show that and then finally we want to make sure that anything that we do in ml net it can be extended with all the mo buzzwords you've heard like tensorflow and stuff so what I'm gonna do next is bringing Bri up on stage and what we're gonna do is we're gonna build a yeah come on we're gonna build a machine learning application that does weather as well yes we are so if we take a look we still have Dan's Blaser app up on here but what we're gonna do is actually make this app smarter using ml net all it does is it right now is it pulls weather data from from Glenn's micro service that's hosted in a Draper Nettie's but we're gonna use machine learning to take images from around the city and actually predict if it's sunny cloudy or rainy so it's gonna predict the weather because we all know that the weather is not always accurate you're better off going and looking yourself to see if it's actually right exactly so we'll close out of all these over here all right so if we go back to let's see the forecast appraisers that we saw before all right so Dan talk a little bit about components which are just UI elements that you can have in your plays or applications and I creative one of those for the machine learning and I just called it ml weather cam that's just gonna go right below the weather data that we saw before and then what this does is it if we look at this ml weather cam don't raise ur right here there's gonna be three buttons that are gonna link to three separate photos which are then going to be put into this classify weather method and if we go to the app it's gonna show you a couple pictures that we got from cams around the area and then it tells us kind of what it thinks those cams are showing us whether it's rainy or sunny or or what not exactly so here you can see there's nothing really implemented right now we just have it returning a string so if we go ahead and run this real quick you give it a second and we'll see that new component added on there it's just when you click on it oh you know what actually we're gonna try it on the server version instead because that's where it's implemented so let's retry that mm-hmm Dan caught you up yeah he really did he really did let me try this again so we're gonna rebuild our solution and it'll take just a second just I want to show you that it's implemented without the machine learning service or machine learning yeah examine the application will show the pictures yeah and then we'll run model builder to go and create the actual model for us right exactly so should never rebuilt the full solution but get a second the big solution is it's a big solution yeah something I should talk about is you know while we have the solution we're actually gonna make this entire all the demos we have the day I'll be available on github later today right exactly buddy watch that keynote can actually do this himself and so here are the three pictures that I was talking about here's that new component and of course it's just returning the same every time so to add machine learning we're just going to use model builder which is UI tool and Visual Studio it's just an extension that you can download once you download that extension you add machine learning and there's a variety of scenarios here that you can see like sentiment analysis price prediction but we're going to do image classification because we want to predict the weather and images so then we'll choose our training data which is how you create the machine learning model in this case I've already put it in the format that it needs to be with three different labels here and we can actually see once we choose that that I have my images here a preview of my images for cloudy rainy and sunny you gave it a bunch of images to learn from great and I'm gonna have it train for about 90 seconds because it's a small data set with larger data sets you want it to train for a little bit longer so this this this whole tool kind of makes me laugh I remember a year or two ago we were building a demo in the team it was a it was called github classifier and what get up classifier did is it basically looked at the issues were being filed in our github repos and would automatically classify them to the right places it's kind of a bots I remember sitting on my team and I was looking at the code and I'm like I don't know if I'd ever be able to write that code and it's kind of the genesis of a model builder thing I couldn't figure out how to write the code and then the next thing was I remember asking the team well how did you choose the algorithm and the answer kind of was well we tried this one and it seemed to work and to me model builder is like taking that to the next step further where you basically instead of doing that give me a data file of existing data run this tool on it it will try things doing it right now it's trying all the different algorithms we have in ml nets and will write the code for me mm-hm so you're making ml where I can use the code right yeah so building and fine-tuning the performance of a machine learning algorithm can be really difficult especially if you don't have that machine learning knowledge so what model builder does is use automated machine learning or auto ml for short to explore different algorithms and settings to give you the best model based on your scenario and your data so it's really really cool because you don't have to have that machine learning knowledge and as well you're showing the graphical version of this inside of Visual Studio but if I am on a map or on a Linux machine I can also drop the command line and run the same tool that you're running with inside of Visual Studio on all those platforms as well right exactly so if you you don't use Visual Studio you can actually use this ml net CLI and any command prompt which is really nice so it's done training we're gonna head over to evaluate screen it actually found this one model here which uses a resonant neural network architecture for that image classification and we'll move on here and so it's really nice as once you have your trained model you can add your projects and if we zoom in here give it a second you can see that there's this console app here which is actually where the model training code is then you have your model consumption code and your actual serialized zip file which is the model so if we come back out here and now if we go back to model builder you can see it gave you the code for consumption right here all you have to do is copy this code and go back to our weather classifier will uncomment the name space that model are actually adds the reference to the model for you and right here so we've created our input we're going to set the file path here it's a full path and then we're going to actually load this into here and return result dot prediction and so actually we're gonna add the reference here because I think it was added to the wrong no it's there let's see what it's giving us here Oh so we've got our Weather Service ml dot model Oh what we have to do is actually I think I called it on the wrong one projects yeah the wrong project it actually needs to be called on this project so whichever project you add machine learning to it'll add that reference to automatically but since I did it on the wrong one we're just going to add the model here and then we'll so then sorry it's a mouse I'm not really used to here so we're gonna do input dot image source equals full path and then we'll be able to do about that all right so now we can see that it detects this CenturyLink Field is cloudy Paramount Theater is looking a little bit rainy and Golden Gardens park is looking sunny so in less than five minutes we were able to use ml net and modelbuilder to add machine learning to this blazer application which is really really cool that's amazing let's go back to the slides and we'll talk about IOT so IOT kind of a new space in net ionic core kind of enabled us by being able to run on different platforms and architectures and so the big thing here is you can run dotnet core on all these small devices where I raspberry PI's including all about net you can run asp.net on these things we have a GPIO library for reading and writing data to some cool hardware that Richards going to show us and you can actually deploy these applications to IOT either directly on the device or using a container on the device so let's switch over here and bring rich on and let's talk about IOT and dotnet hey Scott so this is more of a Show and Tell type of setup today so we we have a Raspberry Pi right here so this is a Raspberry Pi 3 actually and it's got this hat on it sometimes they're called shields but this is a hat or a bonnet and this is controlling this set of led matrices so actually there's four of them here it's really hard to tell because I did such a good job making this set up but there's actually four of these and it's all c-sharp code that is running this from from top to bottom and so the the libraries that we built actually are able to figure out like the address translation to deal with the fact that there's four of these and they're kind of like in this set up and so it's kind of cool we've got a message here about Dona Kampf that's kind of one row then we have this other one with the time then we built a analog clock an analog clock and you can see this isn't an image this is actually a code driven I'm watching the second hand go around and in real time it's amazing yeah so this is this is how you're staying on track right so this is actually a kind of a canvas and then it's actually raining in Seattle this won't be much of a surprise you're following the same service that we showed everywhere else right absolutely right great exactly and then so it's showing it's raining so really what this is demonstrating is this device is like really low powered compared to you know like Intel x64 blah blah blah machines that we've been used to and it's showing that yep you can write c-sharp run it on here and it's capable of like doing a lot of things at once that's the cool part about c-sharp and net is you can actually run it on what arm 32 arm 64 but if you want you can also run it on the big Intel CPUs as well yeah and and it's all the same the other thing is because it's all c-sharp it means that you can actually use the c-sharp debugger that you're used to using a lot of the other solutions out there depend on native libraries and some of those are GPL ours is MIT so it's super attractive to people that work in this county ecosystem cool I'm still super excited by this because we never could have done this five years ago oh yeah totally this is this is definitely new so but we're I'm really happy - happy awesome - thank you back to the slides real quick and I want to happen to be really cool dotnet core is all open source and even though it's open source we actually want to consume some of the open source libraries so there's a couple of references you've heard today like gr PC gr PC is an open source project and we Microsoft have been contributing to that to that project our engineers are working on that project to make sure that the c-sharp support there is first-class at the same time I mentioned earlier identity server identity server is an open source project that helps you add authentication to your AP is and dotnet core we are actually contributing to identity server we actually are helping fund them as a sponsor of their project giving them money you know G RPC we're giving them code identity server we're giving them money via github and then also swashbuckle which is a common library for building swagger for dotnet poor projects if you want to if you want to use any of our rest stuff we can generate rest in points the same way we generated those G RPC endpoints to do that you have to have a library like swashbuckle and so I'm happy to announce that we're also helping fund them as well dotnet 5 so we just shipped out into core 3 and of course the team is super excited we're working on that core 3.1 right now but I want to briefly talk about that net 5 - so you know after that in core 3 the next big thing is you know we talked about xamarin and we talked about dotnet core what if we put all that together into a single framework and so dotnet 5 is the genesis of this the next the next iteration of dotnet will be done at 5 and the idea here is all the runtimes collapsed so we have one common set of runtimes we have one BCL that sits on top of that and then we have all the app models on top of this and so in the.net 5 wave they'll just be one dotnet not multiple nets let's talk about our schedule so we just shipped a technique or three today dotnet core 3.1 is going to ship in late November early December that'll be our LTS that's our one if you want long-term support but we're gonna go way beyond that we want to make dotnet predictable so you can see here now dot at five will ship next November dotnet six will ship to November afterwards so on and so on and so on each of these nets every other year will be an LTS so it's very clear which ones are long-term supported and which ones are faster but we're trying to make it easier for you to consume nets and understand the schedule I do want to do one quick thing I'm going to grab my laptop slide it over here I thought I would do one demo of some of the tech that we have coming in dot net five and so Dan showed the blazer wrap I'll you show the desktop app James showed the the the xamarin app and Bri showed the ml app well we want to take the step this stuff even even further so we're gonna switch to my laptop here he jump out of presenter mode get my laptop back and I want to show a preview of one of the things we're thinking about in dotnet 5 so I'm gonna run that same blazer app that Dan showed but now what I've done is I've actually wrapped it in an electron shell electron is the technology we use to take make things like Visual Studio code run on the desktop and so now you see that same exact web weather application running it's it's it's a blazer application so it's web but it's now running in a desktop window it's got file menus I can do file and exit this is one of the examples of the technology we'll bring in the.net 5 wave so I want to close with one thing here which is we have an awesome unified platform you can build every type of application on dotnet core my advice to customers today with the shipping of dotnet core 3 if you're building new applications build them on top of the core 3 it now has all the capabilities that should be important for modern applications if you have existing applications you're likely should keep them on net framework there's no reason to move them off of Dutton and framework dotnet framework is going to be supported forever so new applications are done at core 3 leave your existing applications where they are everything that I'm showing here is downloadable today and I want to thank everybody very much go get the bits and build some new applications on tanja core thank you very much