Question

Somewhere in my code, I have this line:

return _store.OpenFile(path, fileMode);

With fileMode being sometimes FileMode.Create and sometimes FileMode.Open.
Everything works well, I always get a valid stream and if necessary, the file is correctly created.

But, I’ve just discovered in my VS output that I have the following message every time I call the method where the above line is:

A first chance exception of type ‘System.IO.FileNotFoundException’
occurred in mscorlib.dll

I get this error when the file is created and I also get this error when the file is overwritten (and obviously exists).

I’m just curious about these errors since everything works perfectly.

Thanks,

EDIT: Same thing with new IsolatedStorageFileStream(...). Everything works fine but I still get the “first chance exception” message.

Answer 1

Found the answer.

It’s just how VS debugger works: for every exception caught by a {{catch}} block, a “first chance exception” message appears in the VS output.
So here, we can guess that, internally, the {{OpenFile}} method uses a try/catch block to check if the file exists.