Creating A MessageBox That Doesn't Stop Code?

Question

Ok, I'm looking for something pretty simple: creating a MessageBox that doesn't stop my code.

I'm guessing I'll have to create a different thread or something? Please advise on the best way to accomplish this.

Thanks!

Answer 1

You could spin up another message pump by calling it on separate thread. MessageBox.Show pumps message so it is safe to do without a call to Application.Run.

public void ShowMessageBox()
{
  var thread = new Thread(
    () =>
    {
      MessageBox.Show(...);
    });
  thread.Start();
}

Edit:

I probably should mention that I do not recommend doing this. It can cause other problems. For example, if you have two threads pumping messages then it is possible for the message box to get stuck behind another form with no way to make it go away if the form is waiting for someone to close the message box. You really should try to figure out another way around the problem.

Answer 2

No, You're going to have to make your own message box form. the MessageBox class only supports behavior similar to .ShowDialog() which is a modal operation.

Just create a new form that takes parameters and use those to build up a styled message box to your liking.

---

Update 2014-07-31

In the spirit of maintaining clarity for anyone else who finds this through google I'd like to take a second to explain this a bit more:

Under the hood MessageBox is a fancy C# Wrapper around the Windows SDK user32.dll MessageBox Function and thus behaves exactly the same way (after converting .NET Enums into the integers that represent the same thing in the system call.

What this means is that when you call MessageBox.Show() the call is marshaled out to the OS and will block the current thread until an option is selected or the window is killed. To prevent your code from being halted you need to launch the message box on a seperate thread, but this will mean that any result that comes back from the message box (Yes / No / Ok / Cancel / Etc...) will be returned to the separate thread that was tasked to call the message box.

If you act on the result of this message box launched this way you'll have to Dispatch the result back to the UI Thread for Thread Saftey.

Alternatively you can create your own message box form in WinForms / WPF and call it with the .Show() method. Any click events on the buttons will execute on the UI Thread and you will not have to dispatch the calls back to the UI Thread to manipulate things in the UI.