You can use the Break method of the Debugger class, in the System.Diagnostics namespace:
Debugger.Break();
Now, there’s also a different way you can add conditional breakpoints, without mucking about with adding code to your project.
This of course only works when already running your program through the debugger
What you can do is first add a regular breakpoint at the location where you want your debugger to stop, then right-click the red dot for the breakpoint:
and then edit the condition to fit your needs:
This will then be symbolized with a small + inside your breakpoint dot:
