Now that I have started WPF, I need to rebuild and revisit some of the helpers I have built over the years.
A long time ago, back in January 2009, I wrote an article titled A custom MessageBox showing how to customize the Windows Forms MessageBox.
A few days ago, I needed a custom WPF MessageBox. Therefore, here is something to start you with if you ever need to customize your own.
You can read this new article from http://emoreau.com/Entries/Articles/2015/02/Custom-MessageBox-in-WPF.aspx.