Nice, but (I haven’t looked thought all the code yet, but from what I see) your program tries to open a file on the local system. This is fine, except that if it is running as a partially trusted app it will throw a security error. The way around this is to open an Open File Dialog box and use the get the stream, not the file name to open the file. Same thing with saving (only use the Save File Dialog).
this bug is an OS bug, not mine, the bug also is out of our control, the OS should not allow users to running my app as a partially trusted app.
I’m going to have to disagree with you on that. The OS should (as it does) run anything downloaded from the net in partial trust unless explicitly told otherwise. And Sven Groot is right, if your app needs certain permissions to run it should declare them as such. But for 95% of desktop apps that need to access a file the GetStream method should be used so it can run as partially trusted.