Here is a simple way to make a custom WPF Message Box
WPF RichText Editor with custom Slider Control formatting and a Font Style Dialog box
A message box service implementation that is based on WPF.
A simple example of how to make a custom YES/NO dialog with DialogResult in WPF. Freely (as in beer) available code is on Github: https://github.com/Hitman666/CustomYesNoDialogWPF. The breakdown is that you make a new window (MsgBox...
Avoiding a cumbersome message box or input box that locks the application in WPF.