C sharp - restringir en un TextBox unicamente el signo -

private void textBox1_KeyDown(object sender, KeyEventArgs e)

{

  if(e.KeyValue==189)

   {

       e.SuppressKeyPress=true;

    }

}

Private Sub TextBox1_KeyPress(sender As Object, e As KeyPressEventArgs) Handles TextBox1.KeyPress

        e.Handled = "-".Contains(e.KeyChar)

End Sub

private void TextBox1_KeyPress(object sender ,  KeyPressEventArgs e)

{

        e.Handled = "-".Contains(e.KeyChar);

}