Debug COM dll with .Net app in VS.Net

问题:
I've inherited a COM dll project that was switched from the VS6 environment
to VS.Net. I thought I could debug the COM dll code by adding a VB.Net
project to the solution, but when I set breakpoints in the dll, the code in
the VB test program just passes over them. I'm guessing that it has
something to do with the VB project referencing the dll interop layer,
rather than the dll itself.

Is it possible to do what I'm trying to do? Anyone have any suggestions?

解决:
VS.NET has several debug engines for different purposes:
* unmanaged debugging
* managed debugging
* script (classic ASP) debugging
* ...

Your NET project by default uses the managed debugging engine. Therefore,
breakpoints in unmanaged code will not be hit.
.....
it worked if I checked the
"Unmanaged Code Debugging" checkbox in the VB.Net project settings.....

勾选:启用非托管代码调试

refer to http://www.thescripts.com/forum/thread285211.html