How Can I Simulate Double-Clicking A File To Open It In The Default App Without Installing Default App?

Question

I have an app written with Visual Studio 2013. The app has code for opening a file using the standard OpenFileDialog and also has code (AutoOpenFile()) for opening a file when a user double-clicks on a file that is handled by the app. I have not yet created
an installer for the app, so I won't be able to test it's AutoOpenFile() code...unless there is a way to simulate the process of auto-opening the double-clicked file without actually installing the app on my PC. Anyone?

Answer 1

Thanks for your reply, Wyck. I already have the necessary code in my app for opening a file when I double-click on it. The problem is that the app is not currently installed on my PC. Until I do install it, is there a way I can test-run that code
by double-clicking on an associated file?
You lost me at: you want to test-run code that is not on your PC.
O_o
You want to double-click a file, and then...what do you want to have happen?  You want to run...something...that is not on your PC??
The "simulation" is to launch your app from the command line and pass in the name of the file you wanted to simulate a "double-click" of.
Regardless, you cannot get the shell to have a double-click of a file cause your application to launch unless you modify the registry to do so.  (This is tantamount to "install" to me.)
In the spirit of continuing to be helpful, though, I'll assume that this is what you want to do and I'll show you how to get it done with the least amount of tampering with your registry.
Here are minimally invasive registry modifications you need to make to get it to launch a program when you double-click your file.  It's pretty small.
EXAMPLE ONLY:
Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOT\.wyck]
@="Wyck.Document"
[HKEY_CLASSES_ROOT\Wyck.Document\shell\open\command]
@="c:\\windows\\system32\\notepad.exe \"%1\""
[You have to save the above with your appropriate modifications to a file with the
.reg extension (e.g.: test.reg) and then you'll have to double-click the test.reg file to "merge" these settings into your registry.]
The example above registers a file extension called .wyck and assigns a completely arbitrary class name to it called
Wyck.Document.
Then it associates a shell open command with the Wyck.Document class that causes
notepad.exe to be passed the filename of the file you double-clicked (that's what the
%1 does).  You are welcome to replace all the specific names with your own extensions and class names and replace notepad.exe with the path to your (test) executable.
This executable will be launched, but not with a debugger attached.  To facilitate debugging it, you'll want to temporarily add some code to your program to pause when the program launches, possibly by showing a message box right at the very beginning
of your main function that says "attach debugger now" so that you can attach a debugger to the process that was started by the shell, and then dismiss the message box and continue debugging.
When you are done with your testing, you can simply manually delete those two registry keys using
regedit.