I was wondering if someone knew how to "invoke" this kind of messagebox in C# or VB.NET
Don't take any notice of what is written in messagebox it's in French ^^
Thank you for your help !
What you are looking for is called Task Dialog
. You can find out how to implement them in your WinForms application here.
EDIT:
Oh, look, someone has even created a wrapper to use them in WPF.