Alexandre Laranjeiras rankingfii.com.br

var answer = MessageBox.Show("Close the Window?", "Close", MessageBoxButtons.YesNo);

Do you link viewModel to Window with DataContext?

you are using DataAnottations or FluentApi?

Do you want to work with WPF/MVVM + WCF?

What validation do you want to do?

What database you are using?

what is your connectionstring?

What validation type?

Do you have Github?