I've been struggling with this for more than several hours and cannot think of a solution.
I have an application that can be started in this way:
TestApplication.exe ID={GUID} filename={filename}
If there is not an instance of the application with the same GUID, a new instance should be started with ID={GUID} and the specified file should be loaded in it.
If there is an instance of the application with the same GUID, the user should be asked if he wants to close the file he is working on and if he confirms it - then the new file specified should be opened in the running instance.
Any ideas how to implement this?