Winapp not to run twice

[Scanzee]

How can I make sure, the application does not run twice...
If users try to open the application a second time, It shows a messagebox or something...

Thanks
Scanzee Productions

 

[JohnH]

Check the Application property "make single instance", you could display the messagebox in application event StartupNextInstance.
How to: Specify Instancing Behavior for an Application

 

[jmcilhinney]

The usual behaviour would to just activate the existing main form, which you'd do in the StartupNextInstance event handler like so:

With Me.ApplicationContext.MainForm
    .Show()
    .Activate()
End With

 

[JohnH]

That is the default behaviour, you don't need to add that code, the first instance will activate and display even from minimized state.

 

[jmcilhinney]

That is the default behaviour, you don't need to add that code, the first instance will activate and display even from minimized state.

Even better.