Question

In WPF need to trap the keys entered in a textblock to keep the user from entering anything but digits,cap letters and navigation keys (Backspace, Arrows, etc).

Thanks!

Answer 1

First there is a Filtered Text Control available here that does simple masking

The simple way is to handle the PreviewTextInput Event with something like this.

Private Sub TextBox1_PreviewTextInput(ByVal sender As Object, ByVal e As System.Windows.Input.TextCompositionEventArgs) Handles TextBox1.PreviewTextInput     Dim Character As Char = Convert.ToChar(e.Text)     If Char.IsDigit(Character) Then         e.Handled = False     ElseIf Char.IsLetter(Character) And UCase(Character) = Character Then         e.Handled = False     Else         e.Handled = True     End If   End Sub