Chapter 6: Debugging with Visual Studio TIP If you write a program that is doing a lot of work, or very little work but is stuck in an endless loop that you inadvertently created, you can pause execution by selecting the blue pair of vertical bars button found to the left of the square blue stop button. When you do this, your program stops at whatever line of code it was executing at the moment you selected the pause button. You can then resume from that point. This button works much like the pause button on a remote control or a personal media player.
Customizing a Breakpoint The preceding explanation described how to set a location breakpoint, where execution stops on a designated line in code. However, you can make a program stop executing based on various criteria, such as hit count, conditions, and more. To see what else is available, set a location breakpoint and then right-click the dot in the margin to view the context menu. Table 6-1 describes each of the breakpoint options available from the breakpoint context menu. You can also set a function breakpoint by clicking on the method to break on and selecting Debug | New Breakpoint | Break At Function or pressing CTRL-D, N.
Option
Meaning
Delete Breakpoint
Removes the breakpoint.
Disable/Enable Breakpoint
If you don’t want to delete the breakpoint because you’ll use it again, you can disable the breakpoint and then enable it later when you want to use it again.
Location
This is set when you click in the margin. You can change features of the location through a dialog window.
Condition
Allows you to enter an expression that can cause the program to stop if either the expression evaluates to true or the value of a variable has changed. The expression is based on variables in your code.
Hit Count
Makes the program break on that line every time, after a number of times the line has executed, when the count is a multiple of a number (i.e., every nth time), or when the number of hits is greater than or equal to a number.
Filter
The breakpoint will only be hit (causing execution to pause) for any combination of machine, process, or thread choice that you set.
When Hit
Sets a tracepoint that prints a message to the output window. The message is configurable to include output of various system values like function, thread, and more. You can view the message in the Output window by selecting View | Output Window or pressing CTRL-ALT-O. You also have the option of running a macro when the breakpoint is hit.
Edit Labels
You can associate breakpoints with labels to help organize breakpoints into groups.
Export
Lets you export breakpoints into an external XML file.
Table 6-1 Options from the Breakpoint Context Menu
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