Periodically I hear people having issues with debugging STS code from CardSpace based scenarios. When you invoke an STS by selecting a managed card, you do that from the private desktop; that means that you can;t access your interactive session until the call to the STS returns, but if the STS code is exactly what you want to inspect you appear to be stuck. There are a number of easy ways out from that apparent impasse: I recently shared those with a colleague, and her reaction convinced me that there's some value in sharing those on the blog.
Trick 1: Put a breakpoint in the STS code, launch your client app and get to the point in which you use the managed card. The dialog of the token request will be stuck, since you have a breakpoint that blocks your RST processing. Just cancel the request and exit the private desktop: you will find the execution stopped at your breakpoint and you can go through the STS code. Obviously if you successfully step through the entire code the token will never be returned, since you killed the client, but if your purpose is debugging the STS you should not care. Easy 🙂
Trick 2: Alternatively, you can have the client in a VPC or in another physical machine.
Trick 3: (thanks to Xiao Xie for this one): if you are running on an OS which allows more than one concurrent interactive sessions, such as Windows 2003 or Longhorn Server, just create a remode desktop session on the machine itself. You can run the client from the remote desktop console, and when the provate desktop shows up you can skitch to the interactive session and attach the debugger to the STS
Happy debugging 🙂