Now using tracepoints in Visual Studio 2005 you can quickly and easily associate a custom action with any breakpoint. When the tracepoint is hit, the debugger performs the specified action instead of simply stopping. You can use this feature to run macros or print messages to the output window, for example, without having to add or clean up any code. (If you've ever gotten tired of adding Debug/Trace/Console.WriteLine statements to your code in order to see what's going on, and then having to remove them after debugging, you'll really appreciate this new feature.)
To assign an action, right-click the breakpoint and select the When Hit menu option. This causes the When Breakpoint Is Hit dialog to appear. Here you may elect to print a message (including variables or expressions), run a macro, and control whether to stop or continue execution.