Found one way to do it with wpfBuilder: XAML. Don't have a way to do it just in code yet. Seems like there should be a way to do that. But this serves my purpose. Thanks again for your help, Kevin!
Best regards,
burque505
var xaml = """
<Button xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation'
Name="btnDefault" IsDefault="true"> OK</Button>
""";
Button myButton = System.Windows.Markup.XamlReader.Parse(xaml) as Button;Best regards,
burque505

Help needed: Set DefaultButton for dialog