Prevent input during a process in Windows-Mobile

I have a Window Mobile app where the forms use keypreview and post the form when the Enter key is pressed. If the form post has a delay, the user may press enter again. The second enter is processed when the first process ends.

How can I 开发者_StackOverflowignore the second enter press or prevent it from being queued?

I tried turning off keypreview, but the results were not consistent and the enter key was still processed by the control with focus.

I think this question is probably the same problem (and the answers are the resolution).