hi and welcome back my name is Dante Gagne and I'm going to be continuing the connect learn series on the universal Windows platform application development in this video I'm working with an application it's a little bit more sophisticated because I want to show you how the debugger works inside Visual Studio to just give you a brief look and how you can diagnose problems that are happening in your application we're also going to learn how to deploy our application different targets so we can use the emulators that are built in the visual studio as well as your external devices so you can see exactly how your application is going to work let's go ahead and jump into Visual Studio at this point up till now we've been deploying only on the local machine this combo box up here at the top allows me to choose what device I want to deploy to now the default is local machine assuming you're working on a Windows 10 machine and you're deploying to an x86 architecture now if you're working on an x64 or an ARM architecture it's probably switched over here to device meaning that you can't actually deploy those to your local machine the defaults are ones that you're going to be able to work with so it's not an issue I can go down here and choose device if I have a secondary device that I can connect to and deploy my application to it so if I want to see exactly how it's gonna work on a particular phone that I want to hold in my hand the way a customer would I can use a device entry in the drop-down alternatively I can go down to the mobile emulators which when I select one of those it'll launch the emulator that comes with the Visual Studio Universal windows tools and it will go ahead and side load my application onto that I'm going to go ahead and select one of the emulators and press play it takes a moment or two once I press play because it's going to compile my application it's going to launch a mobile phone load the operating system onto it and then deploy my device over to it so it's actually a couple steps but if you're just patient with me here for a moment there's the running application now I'm just gonna close the mobile emulator because I want to show you that it worked but the kind of debugging that we're gonna do here we can do just as easily on the local target so let me switch that comma box back up here to the local device and I'm gonna go ahead and press play now I happen to already have a breakpoint set and let me explain exactly what those are now if you've worked with two buggers before you're probably already familiar with breakpoints but just in case you're not let me go over the basics while my application is running if I set a breakpoint somewhere in the code as soon as the line that the breakpoint is on is evaluated just before evaluation it will pause my application and switch control over to visual studio now I've already got one created here so as soon as I click this you'll see the visual studio is hit this break point for me in this case it's telling me hey I'm about to evaluate this command adding or removing a breakpoint is as simple as clicking over here over in the left margin and if you notice as soon as I go over a breakpoint there's even a cog up here that allows me to modify how the breakpoint is going to behave so for instance maybe I want the breakpoint to only trigger if I've hit it a hundred times or maybe I don't want to stop execution I just want to output to the debug window hey we just did this you can do all that through the breakpoints settings for these purposes I just need a basic breakpoint so I'm gonna close this window and now I've got complete control over my application I can put the mouse over any variable and you can see over in the window it's telling me hey my category name at this point is appetizers you can use these to figure things out like are you getting unexpected input are you eating values that you shouldn't beginning these commands up here allow me to control where execution is going to go next step into is the most common this one allows me to follow the execution chain into a given method once I'm inside I can press step over because well let's say I know what that method does I'm not interested I can just step over and not have to go through execution of each individual command I can also set another breakpoint later and just hit the continue button and it will evaluate all of the commands up to that point these are very basic debugging commands but you'll find very quickly that when you've got an error if there's nothing better to help you figure out what's going wrong the last button step out of will simply finish execution of the method that you in and return to wherever you were when you stepped into so basically once you step into a method oh wait I already know what this does you press step out it'll return execution wherever you previously were once you've finished getting the information you need you can just hit continue and as long as no other breakpoints are hit execution returns back to your running application the breakpoints in the debugger are a great tool to help you find out when an application is doing something you don't expect get in there and diagnose what the issue actually is the debugger is absolutely invaluable for figuring out what's going wrong in your application but in the next video I'm gonna take the next step and show you how to debug the more difficult issues like performance I'll see you then you
No comments:
Post a Comment