Question

Ok so I have this weird problem, and I’ve searched Google many times for an answer but to no avail… Anyways I have this problem where I can’t seem to get my program(s) to show me error messages when I want. This has happened on many occasions and eventually figure out that its a variable that’s null, but for some reason no error was thrown?

Here’s an example of one I just had.

Person clicks a button to show a new form called debug.

Debug debug = new Debug();
debug.Show(this);

And this was in my debug form.

public new void Show(IWin32Window owner)
{
    base.Show(owner);
    Parent.Move += new EventHandler(delegate(object sender, EventArgs e)
    {
        Location = new Point(Parent.Location.X + Parent.Width, Parent.Location.Y);
    });
}

Long story short, the code didn’t work because Parent was null but it never even hinted that was the problem.

I’m sure there some explanation but I have yet to find one in my Google searches…

Answer 1

You can also try the following in Visual Studio:

1. Debug > Exceptions
2. Expand the “Common Language Runtime Exceptions” entry
3. Expand the “System” entry
4. Click the checkbox for System.NullReferenceException
5. Click OK
6. Run your application with the debugger attached.

It will now cause the debugger to break whenever a NullReferenceException is thrown.

I would guess that either your Application is wrapped in a try{} catch{} or, somewhere at the base of the callstack that results in debug.Show() being called, the code is wrapped in a try{} catch{}