I'd like my dialog to close when it receives WM_CLOSE, so I have the following code:

[code]case WM_CLOSE:
EndDialog(hwnd, WM_CLOSE);[/code]

But I've also noticed that If I were to do:

[code]case WM_CLOSE:
EndDialog(hwnd, 0);[/code]

It seems to work just the same way, that is, it closed out the dialog without an issue.

Is there a "right" way to do this or does it not matter?

The second parameter you pass to EndDialog is the value returned from DialogBox.  It has no system-defined meaning.

Thanks Skywing, that's all I needed to know.