textbox should accept numbers only

1. write the code below in your textbox keypress event

private void txtPincode_KeyPress(object sender, KeyPressEventArgs e)

  {

      if ((e.KeyChar >= 48 && e.KeyChar <= 57) || (e.KeyChar == 8))//keychar 8 is for backspace

            {

                e.Handled = false;

            }

            else

            {

                e.Handled = true;

            }

  }