Debugging Tricks

Let's delete all the breakpoints we have so far and 0:00 I'll show you one of my favorite ways to start the debugger. 0:03 We can right-click on the line of code that we want to break at and 0:06 click Run To Cursor. 0:11 The debugger starts and runs to that point. 0:15 Another neat but 0:18 dangerous trick is to set the next line of code that should be executed. 0:19 Let's say we're here and 0:24 we want to just skip to the add song method without calling menu dot prompt. 0:26 That way we don't have to type in the console. 0:32 I can just drag the yellow arrow here down to this line. 0:35 This sets the next line of code to be executed. 0:40 Unlike using the Step Over button, the code between where we were and 0:43 where we are now isn't executed. 0:48 So the Menu.Prompt method was never called. 0:50 As you can imagine, this can cause some problems. 0:55 Let's step into the add song method. 0:58 Again, let's say we don't want to have to run these prompt methods. 1:01 Another way to set the next line of code to execute is to right click on the line 1:06 and click Set Next Statement. 1:11 Now, we just jump to past these lines here without executing them. 1:13 Hovering over song name and artist shows us that they're both null. 1:17 That could be bad. 1:22 Never fear, we can just set their values here instead. 1:24 Now, if I click the step over button, this song will be added to our list of songs. 1:35 Let's jump past the end of the loop and skip this prompt. 1:40 Now, I can use the Step Out button to bring us back to the main method. 1:47 We can also go backward. 1:52 Let's say we want to go back to see this prompt. 1:54 We can just drag the yellow arrow up here. 1:58 And then, press the Continue button. 2:01 We usually want to see how the code runs without us interfering too much. 2:06 So using these features can be problematic. 2:10 But as you can see, it can also be quite helpful. 2:13 You can also use this trick if you're stepping through the code and 2:16 you identify what might be causing the bug. 2:19 You can experiment with different and variable values and 2:22 ways to the code by using these features of the debugger. 2:25 In debuggers without these features, you have to stop change the code and 2:29 then rerun it. 2:33 Some it can take a long time to get back to where the problem is 2:35 only to find out that the bug isn't fixed. 2:39 Visual Studio has another great debugging feature that allows us to actually make 2:42 substantial changes in the code without actually having to stop the debugger and 2:46 start all over again. 2:50 This feature is called Edit and Continue. 2:51 Edit and Continue is a feature that can be enabled or 2:54 disabled in Visual Studio's options. 2:57 To make sure that it's enabled, go to the Tools menu and click Options. 2:59 On the left side of the dialog, scroll down to Debugging, then scroll down to 3:04 the Edit and Continue section down here Here we see that it's checked. 3:09 We can't change the value of this option while Visual Studio is in debugging mode. 3:14 Let's set a breakpoint back here on line 21. 3:20 I'll enter an option so that we get to the switch statement. 3:23 Let's say that at this point while debugging, 3:27 we notice that we accidentally had these two methods swapped. 3:30 We can fix this right now without stopping the debugger. 3:34 We can move the AddSong method down here. 3:38 And we can move the DisplaySongList method up here. 3:45 Now, if we step through this code using step into, you'll notice that we now enter 3:51 the DisplaySongList method instead of the AddSong method. 3:56 This is really handy when we're debugging and 4:00 notice things that we can fix right away. 4:03