Public Class Form1
 
    Dim a As Integer
 
 
    Private Sub TextBox1_KeyPress(ByVal sender As System.Object, ByVal e As _
      System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
 
        a = Val(TextBox1.Text)
 
        If Not "1234567890".Contains(e.KeyChar) And Not (e.KeyChar = Chr(8)) _
          Then
            e.Handled = True
 
        End If
 
    End Sub
 
    Private Sub cmdAnzeigen_Click(sender As System.Object, e As _
      System.EventArgs) Handles cmdAnzeigen.Click
 
        lblAnzeige.Text = a
 
    End Sub
End Class