.NET Standard Revisited

I think there's still some confusion around dotnet standard particularly around why it was invented and how it affects the apps you're currently building on this episode of visual studio toolbox Kathleen dollars gonna do her best to clear up that confusion hi welcome Visual Studio toolbox I'm your host Robert green and joining you today is Kathleen dollar hey Kathleen hi how are you doing great we've talked quite a bit about dotnet standard we being Microsoft emo has done several videos on channel 9 it was featured at connect you talked about into conferences and yet I think there's still some confusion about it and yet and yet so what we had to do in today's show is clear up some of the confusion not so much about how it works because I think that's been covered very well but more about the why it was invented why and when people should care so you know just for example if I'm maintaining existing wind forms of WPF apps do I need to care about this well to start with if all of your code is in your wind forms up and your WPF app you can't use dotnet standard it's really not in the picture but on your wind forms app or your WPF app you might have some of your code in the wind form and WPF application itself in that in that entry level in that entry point and then you might also have some class libraries that you're using that I've already written you've already written or now I inspire you to split them out and put them into something but you've got now this class library you can take the class library and have it target dotnet standard and that's what that's what you can do and we could talk more about why you want to do that right so do you want to go there now or do you want to talk about all the other ways you might wind up caring about dotnet standards another example okay so I do a bunch of xamarin and I do file new project there's always been two buttons shared project and the other button which used to say portable class library right and magically it said dotnet standard library I always choose that one because it's not the shared project right then I do the exact same things I write the Aksum co2 put the code and the sam'l in the exact same place and when I build the application I understand its using.net standard instead of a part of a class library but I haven't done anything different so so in that case that's great behind the scenes you are using dotnet standard instead of a PCL and there are some key differences between the two so let's start off with why that happened why portable class libraries alright anybody checked when we did a an episode on it a couple of years ago they were awesome so I'm ceremoniously dunk yeah how did they do they were actually pretty cool so they were great it's just that dhania standard he's that much greener in that much cooler so let's talk about the difference so portable class libraries walked into a world where there were a lot of frameworks and across all these different frameworks there were different rules that API was just a little bit different okay so what a PCL does it says those things you have in common you can use right if it's not in common between these two things you can't use it and if you add a new target you're going to change what you can do so you could have like dotnet you would use PCL and it could be like xamarin and something else and you're out there in the field and everybody's happy and all of a sudden somebody says let's target Silverlight and then as you add that other requirement in you lose a bunch of api's and you can actually break yourself in the field so because PCM was always an afterthought they don't fit into today's world as well as we want them to so everybody took a step back and they said well instead let's create the standard ahead of time that html5 is a standard okay that's what a standard is it's basically a word document somewhere so there's a dozen standard people got together and said this is the things we can agree on and there was a lot of work to actually get the right set of features in that now if any platform any framework is going to say I support dotnet standard they have to follow those rules so instead of being an intersection of what was already written it's a standard that then gets pushed out and people have to adopt now that doesn't mean that dotnet saiful framework or xamarin has to make internal changes because it doesn't matter how they implement this it can be any way in the world a lot of the zamarons stuff actually pretty well aligned and so it can just call straight in and it's just fine for the rest of the stuff there needs to be for like dotnet framework there needs to be a redirect so it says oh you said you want to call this but I know what you really mean is this API that's just a little bit different and will just redirect you over there weird weird surprise Robert me on that one okay I'm I write some code hmm targeting what I think is the dotnet framework but I'm not okay I just said if you're targeting dotnet standard you're actually targeting dotnet standard it's what we call a reference DLL and let me show you real quick what that looks like so if I come over here and I go to the dotnet standard this is actually github dot net standard pick one which one do you want to pick just am not data will do data okay so I'm just going to open that just open it no right-click just open it come on okay so in this opens you're going to see the actual coded on it standard so it's a standard it's a document it's a document written in code okay you're with me yep all right so this is what actually looks like and it has enums because of course we need those to define the API surface level okay but it also has a class now there's something kind of unusual about that class it doesn't do anything right it's either empty or it throws okay that's it so a reference library is a library that's empty so this works just fine you can target this and Visual Studio or your bill system or anything that needs to understand your libraries can look at this and go hey I get it okay because they don't care that nothing actually happens and then when you go to run on your full framework machine then it's this is called net standard DLL that's what this builds so when you that's on your your box where you're doing your build and then you go to production and you go over and whether it's a Linux box or a Mac box or a Windows box goes there and it says well there's an standard DLL associated with the framework I'm running now use that and at standard DLL which doesn't have empty places okay instead of the one that you compiled against so inside of those brackets it may say oh don't do this do that okay so the brackets here may call a different API or an API that's just in a different spot and all of that gets worked out however the that framework wants to do it the only requirement is that there be a net standard DLL specific to that framework so that when you write your app and you target net standard DLL and you target this empty reference library it can get thrown out and a real one that actually works can be put in place now the purpose of this document here is to set the rules on what you can call just like a portable class library said you are allowed to call this subset and if yes if you try to write something that isn't supported you'll get a compiler error because it doesn't exist this is now a better more flexible way of accomplishing that right yes compile time if I call something that isn't in thought Nets standard and I've said I'm targeting dotnet standard right then I'll be alerted that I'm calling code did doesn't essentially doesn't exist in case he calls that's correct yes so all of that works very similarly and the difference is that with PCL there was no way to change the API surface if it was just a little bit different it did the same thing but it was just a tiny bit different kind there wasn't a way to really resolve that in a PCO world now we resolve it because on the machine that's actually running we're house actually executing it's not empty there's something in there and whatever that thing is it might just do the job if it's simple it might ask something else to do it it might do a there's even some binding redirects and things that can be involved and so all of that stuff happens behind the scenes that's part of what Iman talks about if folks want to see that on the in his videos because he wrote this stuff he really understands that deep level what what I want us to talk about is why people care and what's the when we step back was the impact this on individual developers going forward so just like with portable class libraries the main impact is one of the main impact servers that the main impact comes if you're writing code it's going to run on multiple platforms it is a main impact that the main impact it's not the only impact but it is the main impact and the other impact comes from the fact that this is also a statement of what Microsoft has determined is the commonality across platforms so another way we can say that is this is the definition of the future for the non what I'm calling an entry level but the non UI pieces so for everything else including some things around console apps for all of these things this is what's defined as where we're going in the future and so even if you're not actually going to run on a different platform if you go ahead and target dotnet standard then you're able to say hey I know I'm within the bounds of what the future is likely to look like and if it's something that's outside of that then I can look for some help for how I get that job done okay because it doesn't its standard 2.0 and there's been a couple of iterations of it was not randomly created a lot of code was evaluated in order to see what do people actually do and it covers the vast majority of what people actually do so if you're writing an application and you say oh I want to do this thing let me see if it's in dotnet standard let me see what to do a little different for it to work another standard and this also supports some of the deprecated and out-of-date ways of doing things so when we look at areas like XML and areas like that we've had a few iterations of how to approach those and this lets you say hey this is the one that I expect to use going forward so where there's something missing there's often a replacement that is a better way going forward okay so I'm working on an existing WPF ever I'm creating a brand new WPF F and I want to build a class library uh-huh I can just build the class library the way I always do not worry about dotnet standard I have access to the full framework from within WPF and I can go and do that and if yes ciello is only ever going to be called from that WPF app then I can just happily do that and not have not need to think about that NIST standard and if I don't think about it I haven't lost anything and the only thing I'm in a challenge on that is I'm gonna say that it's very hard for you to say never ever anybody else will ever want my class library it's easy to say Robert but let's look at the world around us and how much change we've seen and your class library is important in your class library you want it to last for five or ten or fifteen years so if you want to write it with that kind of thinking and you say well I'd like to still be on WPF in 10 or 15 years and have that still be cool but I don't really know what's going to happen there I do know that the core way that we write applications has been pretty static now for a really really long time and Microsoft has found a way to move forward across a lot of technology change using pretty much the same code and the API is is now this is an API level conversation and this is a way to say the api's are going to have a pretty long life not that they'll never change it's just as skin as it's going to change in a very slow level so you do the best job you can to say that my WPF app that work in the background this business logic that extra work that's going on I'm going to future proof that by having it understand dotnet standard now you don't actually have to target dotnet standard you can you can do this a different slightly different way if you'd like you want me to show you how you can yeah okay I can about that in a second so I decide okay future proofing is probably good right so I'm going to target that nest in and I'll create the closet a heat class library targeting a standard so finally project on its standard library I assume right exactly and I target the latest version of the dotnet standard source depending on what version of Visual Studio I'm in right because each version targeted a different version of the dotnet framework but the dot knits how do I know that dotnet standard to supports all of the things that I would have done in my app if I was directly going against the framework am I going to are there things not available to me and is there a way to know that ahead of a time there is more than one way to know that ahead of time so I'm going to open a new browser window here and I'm going to type api's api's of dotnet mm-hmm I'm going to go there and what is your favorite what is your favorite class or method in in side of net so it's gotta be something in system dot data you like system data I do that let's get a little more so let's go to link link yeah okay and let's go to I don't know pick one of those okay we'll just pick anything we'll just pick a refresh mode refreshment table payment no table no idea what we're gonna get here so let's just pick that come on we can do this okay so what we've got done is we've gone to a evaluation of the API itself the API surface layer itself and so we can see the what this class is when you find out some things about it we can find out how many people use it okay so 0.3% of users in one of the ways that this gets evaluated so this information was used in order to build the surface area of the of the.net standard okay and so they also make it available because Microsoft has a at least the dotnet core we share our sin of apps points very high that does not very high this is does not get used very often well this is system data dot link and that's not a real common thing okay we can see where it is it's in.net full framework yeah 3.5 and for coming forward all the way it's in mono and it's in Windows Phone Silverlight okay okay now I'm going to pick one my turn so I'm gonna look for system system dot string and I bet yours mine is more but this is you know this is rig this is a rig a mobile four okay okay so we can find out some things about the system that string class and we can look at its usage and I just wonder about the 15 or so percent that don't use a string but most things use a string most applications use a straining not surprisingly now let's find out some more things about it it's in.net core remember yours was not in net core so now I can see so when I know the actual the actual thing I'm looking for I can find out where it's used okay okay this is one of the things you might want to do more commonly I think what you're going to want to do is look at your code to see hey well this past muster will that can this be a dotnet standard applicants to be a dotnet standard class library what am i what am i using and how would that go and there's something called the dotnet portability analyzer which you can get off of I click this so you can see it go it's in the gallery Visual Studio Gallery or marketplace I guess we call it marketplace now and I have that open I have just a little silly little sample this is just a one of the links samples and I just grabbed one randomly so we could see what's going to happen when we run this so because I have installed that tool it's a physics it's a normal installation because it's installed when I go to the solution Explorer and I right-click I have an option to analyze okay I also have an option to set settings so let's do that first because it helps show what's gonna happen here so this is a kind of an ugly dialogue but you can see what it does you get to pick what it analyzes look at all your choices Wow okay so if you want to know if something will run on Windows Phone Silverlight 7 you can find out ok okay so let's come up and look at the ones we care about which is dotnet core and I've got dotnet core 2.0 clicked I think I'll also do dotnet standard 1.4 1.5 1.6 and to those seems like some pretty good so pretty good pretty good ones okay unless there's something you see there you just really want me to close mine okay so because I've got that I'm gonna cancel out of this dialog because I made no changes I'm gonna right-click and then I'm gonna say go ahead and analyze and if assuming I have an internet connection because this does rely on internet connection and I could doesn't it it found the Internet it was just fine if it doesn't have it connection then you're going to have to find that before this works because it's real time it looks it up right away so now what I'm going to do is open the report and it's going to open because I actually had an option in that dialog that it would open in Excel right so that's how it knows to open this and it's a little small for being on screen here so let me just make it a tiny bit bigger and what we know now is that the dotnet core it's a hundred percent compatible with that dotnet framework and I click this so up at the bar at the top you'll see that this is dotnet framework right there click that this is the dotnet framework dotnet standard 1.4 1.5 and 1.6 this is dotnet standard 1.6 and dotnet standard - oh okay so you can see that's 100% compliant with - and not the others because 2 contains more than the other sitting right so something's going on here and you're going okay so that's not very helpful yet should Cori I can't fix my bursting but it I can't x-men don't know what the exact question you asked which is how do I know what I need to target I've got code and I want to know what I could target I do know that now and I know that I can target dotnet standard 2.0 right now out of the box and code as it exists no changes okay but the question I'm probably going to want to ask if I'm interested in targeting something lower is yeah what did I do right where did I mess up where did I cause a problem and so you find that on the details tab so when I switch to the details tab and again I'm going to click this up just a little bit not that far see if I can't get it we'll see if I can do that let me just use this mouse over here see if I can get a little bit better at this okay that's probably good okay so now what we can see is that the description attribute in the category attribute each of which was used twice in the sample is what's the problem and I can then go over to here and find out where it came in so in dotnet core and dotnet core it came in in 2.0 because in the.net core column it says supported in 2.0 and above in the.net full framework it was supported in 1.1 and above okay I haven't seen anything that's one point now it made one point one maybe the baseline and then for dotnet standard it says it's supported 2.0 and above which is exactly what the previous page told us is that we need to go to what is it that is supported join operators no join operators is the name of my assembly yeah okay that's the name of my so let's go back we're talking about it so it does not tell me the line of code it simply tells me what I'm doing so now I can go and look for where I'm using the description attribute and the category attribute and that's what I know I have to pull out in my app so I could just use a search or something to find this okay okay okay so now I know what it is I'm using I love doing feature requests there if I could could actually know the lines of code that and then compiling it would show me the actual line red yellow green squiggly is exactly code so I realist in the task list yeah cool that would be that would be great if you want that one way to do that is to try to target what it is that you're interested in and then if you target it and it doesn't work out then you're going to be able to go straight to that code and then this one I might do that for this application it doesn't seem like it's going to be a huge wall of problems but now I know if I bring my application up in here and you might want even run a unique to find out how many different things you're using and just how big the jobs going to be to take your application into the dotnet standard or anything else you saw that list you can check out in it I mean there's a bazillion different frameworks that you can select there to see how your code lines up with and you can take code you've currently you've previously written right correct take you know go and find representative samples of code you've already written mm-hmm put it into a dotnet standard library or run the analyzer on it don't you move in yeah you don't have to move it yet yeah and then when you discover that there are hopefully fewer but maybe more incompatibilities than you thought then you could actually that is a dotnet standard library try to compile it and go see what code doesn't run if it's too much then you then you have the choice of either not doing it or figuring out how to accomplish the same thing with code that is supported correct and and I would suggest that just about everyone who already has a class library should think about doing this because it gives them information for that moment that their boss or somebody says oh I heard about this dotnet core thing and if you know that man you've got problems and you already know that then you know just wave off the conversation and if you know hey we don't think we're that far then you can say and we might be able to do that but the problem is going to be what we're going to do on our on our UI side because we don't have cross-platform UI we have that is very specific to what you're doing and so if you're on if you're running xamarin and then that's great and the Samer can call into a class library and then you WP or WinForms or web forms can call into the same library which can see a scenario you have a desktop client application whether it's uwp or WPF or WinForms or you've got a web app with middle tier code and now someone says we want to put a mobile front end on that let's reuse the logic exactly exactly that could easily happen and hopefully does easily happen that is absolutely what dotnet standard is designed to do this makes it a lot easier for you to target that scenario dönitz standard is the set up to target the scenario and there's these tools that are set up to make it easy for you to first of all just assess it's just I have no idea I've no idea how I sit do I have to convert and then see what goes wrong and fight through that or is there a way that you can just in just a couple of minutes give me a report which is what the portability analyzers for most people it's going to take longer to install and run across there okay so it's a pretty fast tool so there's one more thing that's also available in the analyzers which I'll show you real quick which is if I can close that okay there's something else I also have installed which is just an analyzer and analyzers are installed per project where the tool I just showed because it's actually a visual studio tool first of all doesn't run in code sorry and second of all it does it's not per project it's always available after you install it but here I have an analyzer I mean just get that open here if I go under references and I go under analyzers I have one installed which is called the compatibility analyzer I'll move that over something to see it it's a compatibility analyzer I get that off a new gap because that's where we get analyzers and so now if I use a great variable name I use my favorite variable name uh-huh and like I'm going to say new web client that happens to be a deprecated API so I can find out that it's needed in what its deprecated in dotnet framework okay okay so dotnet standard doesn't have deprecated things they're not all the definitions got left behind so now I can hover over that and I can see that that's that's deprecated and it shows up on both the VAR and the the new because the VAR is effectively telling me web client again so in both cases it's a deprecated type so those are the three big tools for helping you stay in the rails of what you really mean to be doing so that's an interesting thing to do as you're writing if you're writing currently writing code that's not targeting standard yet but you want to prepare yourself for a future where you might get this analyzer on right it's a green squiggly it'll still come trial and you're told as you're writing code guess what this isn't going to work and don't assume it will work perfectly well targeting the whole framework which you're currently doing your apps gonna run but it's letting you know that the code you're writing is not compatible with dotnet standard and it's gonna it's not going to show you everything that's not compatible with diagnose that it will show you all the deprecated stuff is a big chunk okay so if you put WinForms code in here that would not be compatible with on its standard but you wouldn't get a green squiggly because you would still be targeting dotnet full framework to get the ok norms there all right okay so now the big gnarly table that everybody shows but not only tailor yes I do okay well let's come over here to and open a new browser window because I want to actually kind of show people how to find this as well okay because we'll put some links up yes well you know we're not always they're not always going to come back here and so if you just say dotnet standard version table okay that's pretty easy if you hit enter there you will see something in the docs yeah you get some tables too that's okay you get some tables but it's this standard that versions empty yeah the dotnet standard any thought that we didn't go far enough making net Mouse so we had to make Mouse dotnet so we literally made table dot yeah all right okay do you all see the pretty one no you want to see the ugly one is there a pretty one there's a prettier one let's see the pretty one it's right up here with this little tiny lighting is this Internet let's go to the interactive let's just get colors okay okay so alright mystified by this one is the other one by now less so this conversation several times yeah okay why what is this telling me what do I do with this besides go get some aspirin okay well this is not as bad as it looks although I do understand that on first blush this is actually looks pretty crazy so the first thing is that I dice just like to say that by default dotnet standard 2.0 is green good to go okay so dotnet standard 2.0 is really where a lot of things came together the platform support dotnet stain or two dot oh that's the one that was based on these evaluations of what real code looked like it wasn't like what somebody thought was going to happen a lot of stuff happened for dotnet Stan or 2.0 to sort of be the place to be if you can be okay so for you you're writing winforms WPF apps and you're just interested in what full frameworks you can run on other than that you don't care right you're not worried about reach you're only worried about where you're at at this moment so if you are on dotnet full framework 4.6.1 or above you're good to go okay because 4.6.1 is in the table next to framework under two so you can target dotnet Stan or to not uh assuming that your you that you were running the actual framework on your production machine is dotnet full framework 4.6.1 or above but not everything in 4.6.1 is in standard 2.0 right but dotnet standard 2.0 is supported by full framework 4.6.1 okay so if you if so if your oh I see so if you yeah so if you let me let me say this yes come correct so if you've targeted down to standard 2.0 and on the machine you have 4.6.1 it will work it will work I want you back at your 5:1 on the machine there are potentially things that you wrote - that aren't in there but wouldn't your compiler of caught that in the first place no because your compiler is looking at net standard 2.0 DLL the reference DLL I showed you earlier so it's compiling against net standard DLL 2.0 and dotnet full framework 4.5 dot one does not have a net standard DLL 2.0 it has a net standard DLL 1.2 and it says I can't even start I can't do anything I try again and so if you want to stand for whatever reason if you need to target dotnet full framework 4.5 dot 1 you would have to use dotnet standard 1.2 okay and for most people at that point I'd say what are you going to gain from it if you can target 2.0 then you're sort of in this nice friendly space but it's much more painful I'll show you a little bit about what that pain looks like so we're going back to 1.2 oops I need to be that's not what I needed to click so we're going to try it again we're going to go here and we're going to say 1.2 ok so now you see all of the things that you can run on there's a lot of things now that you can actually run on ok but do you remember what the blue bar at the top looked like before was all the way across right that's like just a bar graph of what's available to you so you have 30% of your api's are available 70% are not available so you're gonna have problems you're gonna run into something you're doing that is not supported and so if you have a compelling reason to do that hmm I can give you one compelling reason if you were a library author planning on some putting something on nougat right and you wanted as many people as possible to use yours yeah and you tested with the analyzer I showed or some other way you just targeted to see what happened and you said hey you know what I can do it no problem everything I want is in there then at that point you can target dotnet standard 1.2 have the broadest possible reach and you haven't hurt yourself right but for you writing your win forms or WPF ever I'm going to say what are you gaining you know why you trying to do this if you're back here so 2.0 is really the the the sweet spot and I do want to just say with a little caveat that 4.6.1 up until 4.7 the the way that the the location of things were shifting around on a couple of pieces inside the full framework that caused a bit of headaches for dotnet standard so the dotnet standard DLL had to be aligned with what was on the machine there was a couple of things that it just wasn't quite wasn't quite as solid as you want your production machines to be so you might want to still target dotnet full framework 4.6.1 or for that 6.2 or 4.7 I guess and then use that analyzer to see if you're ready to go and then maybe look at actually targeting net standard in like the 4.7 one a 4.7 - time frame because these these shifts around that needed to happen just to get us fully on to net standard they're done and so there's a little bit of time in there where the it was just not as solid as you probably want a production machine it's not I don't want to scare you on that it's just that some things move from out of box to in box and that was a challenge for dotnet standard because it was here and now it's there and a few things like that just wound up with it with a few problems and just keeping those problems on production is a great idea so let's let's close with how often dotnet standard will change all of the things under here constantly changing there's a 4 7 foot there's a 2 1 core coming out iOS 11 is out in Visual Studio will have support for it potentially by the time this post if not even after that Android 9 is gonna be out eventually you WP there's a new version which is a couple weeks away or so I'm told some of these other things don't change well the dotnet standard change every time one of these changes okay that's a great question so first of all let's be clear that all of those numbers are anything higher than that will also support so immediately right now you know 4:71 2.1 of dotnet core which is available in preview right now all of those things support dotnet standard - oh right now so all of the numbers in that column is those or anything greater so when iOS 11 comes out then there there may be a little bit of work that has to happen if there's again these things when things move that standard has to point to the right spot the net standard dll on you know that might need a little bit of tweaking I can't promise that won't happen but people working very hard for that to be smooth and not so is that the standard 2.0 one or a 2.1 because one of the interesting things is if you remember all of the bracket curly brackets are empty in the reference dll okay and so Dinah standard itself will never have a patch release because there's no code to patch it only has changes to its API surface layer because it is just an API services so that standard only needs to change when there are api's that need to be added to it that yes it doesn't necessarily happen just because iOS went from version 10 to 11 or Android went from 8 to 9 or UWP went from 10 oh 16 to 99 to 0 17 blah blah blah right and so the the interesting thing about that especially for right now because we're you know in a lot of conversions in so many numbers in the air and it's all very confusing is that dotnet core is in preview on dotnet core 2.1 it's moving forward but there haven't been any changes right now to dot it standard so dotnet standard is independent of dotnet core and it will stay on dot nest an or two dot o-- for the next in the next foreseeable future the next few months at least until there's something so we have span now in dotnet core updated versions 2.1 of dotnet court has span and all of its friends and or to oh it is not in standard to okay but that's the kind of thing that would push dotnet standard into net Stan or 2.1 and there's going to be a little bit of a I think a conversation about whether dotnet standard should be aggressive in versioning and as soon as somebody has an idea when we look at uses yeah why don't we go look at percentage of existing apps today use span it's probably a less than system data dot link so I think there's priests over time but I think there's two pieces that are super important one is exactly that right and the other is remembered inot standard in and of itself does not matter it only matters from platforms supported so if you create a dotnet Stan or two dot one and the only thing in the planet that supports it is dotnet core 2.1 did you gain anything right because nobody else can use it so it's not just people using span but it's also other frameworks being ready to support span or you know whatever the API is I'm just using that as an example and so it's when those kinds of things start happening that we want to see dotnet standard evolve so the new features that I could use cross-platform if you just let me our end on it stand or have the ability to extend it because I believe Dutton it core there's the ability to extend it to call missing pieces of the framework is that correct so there's a couple of things you might be referring to there one is that there's a compatibility pack which is Miss named which is Miss named I just want to say that I had nothing to do with his name it's called a windows compatibility right so you'd think it was just for Windows wouldn't do ya know about half of it will also run cross-platform code and half of it will that is a way of adding things that aren't in core and call I'm your coach so you can potentially see something similar for standard you want span that's not in standard yet here's a way to kind of shove it in on the side so that might happen in the nature right now it that would wind up being something through a through new get that you would be getting a span that made sense in your world and as of today that's that's not something that I see out there at all I think that as we get into done in standard I mean our first step is just to explain this crazy thing and have people understand it and understand why they care and then we'll see how it evolves as we see what people ask for is they start really hopefully embracing it and embracing a way that there's no reason to write your application class libraries anymore that are specific to a framework unless there is a reason right so there's no they used to be that was the only way to write it and that was not a problem when our frameworks were like all over the map and hitting really different targets so Windows Phone versus pro framework those are really different but now we have dotnet core and dotnet full framework and they both run on a Windows machine and you're already figuring out which of those you want to do and dotnet standard gives you a way to say that decision can be a kind of temporary decision it doesn't have to be a locked in stone decision for your class libraries cool so yes we're out today right thank you I think this I think this cleared up a lot of the confusion I hope it did I think it's good to see you confused if I'm confused you can imagine viewers are - it's not just about me it's not just about not just about you Robert I hope you enjoyed that and we will see you next time on visual studio toolbox [Music]