Question : How to make a windows application modal?

I have a single-form .NET Windows application written in C# (.NET 3.5) that is opened by another application. I need this .NET application form to be modal, that is, that the application cannot be closed until the form's "submit" button or the "cancel" button is clicked. Ideally, it would be nice if the application would be modal only for the calling application, but I'll settle for it just being globally modal. I'm thinking that this should be simple, but I couldn't find an answer online.

Thanks in advance for your help.

Answer : How to make a windows application modal?

Hmm, I think Windows environment is such that you can open > 1 apps at a time and switch around these apps as you like. So I think the only way is to make the form part of the calling application, and make it modal (within the calling application scope only).