How to wait for form to close without ShowDialog()?

Question

In my program I use WebBrowser control for OAuth. It's located on vk_auth_window form. So in the code I call vk_auth_window.WebBrowser1.Navigate(vkauthurl). If authentication is successful, I silently get token, but if user is not authenticated a form vk_auth_window is showed to them to enter username and password. To check this I catch _DocumentComplete event and check for the right URL. I need no other code being executed until the user finished authentication or closed authentication form. ShowDialog() does the trick, but it somehow hides cursor from username and password fields in WebBrowser control. So I introduced a variable Dim showform as Boolean=True in and set it to False from the _DocumenComplete event and in the main code I use infinite loop.

While showform
       System.Threading.Thread.Sleep(100)
       Application.DoEvents()
End While

However it makes userinput slow due to thread sleeps. And If i remove them, it loads CPU quite a lot. Is there a better way to wait for form to close? What is it?

Answer 1

Do not use a Timer. Events are made for this. You have to subscribe to the FormClosing event of your Form. The code that should be executed after the window is closed has to be in the event handler method.

Use the AddHanlder keyword.

AddHandler yourForm.FormClosing, AddressOf FormClosingEventhandler

Later use the event handler to proceed:

Private Sub FormClosingEventhandler()
    'proceed here
End Sub

http://msdn.microsoft.com/en-us/library/system.windows.forms.form.aspx
http://msdn.microsoft.com/en-us/library/system.windows.forms.form.formclosing.aspx