WinForms - Will there normally only be one instance of MainForm?

Will there normally only be one instance of MainForm?

I need to hold it as a static variable re this issu开发者_StackOverflow社区e I have

Yes, there would normally only be a single instance, unless you specifically create more instances of it in your application code.

Even if you have multiple instances of MainForm, if you declare a variable in the form as static (and not ThreadStatic), there will only be one copy of that variable.