c# numpad acts like keyboard

Question

I am trying to come up with a code that will, depending on what key is pressed in a read-only text box, add or subtract 1 to other text boxes. My problem is I need to differentiate the numpad #(0-9) from the #s above the qwerty keyboard. When I use the code below with NumLock ON the numpad number acts exactly like the other number(subtracts 1). When NumLock is OFF it does nothing. I want it to add 1 when I press a numpad # and subtract 1 when I press a non-numpad #. I've tried Google-ing the answer but I couldn't come up with anything.

Thanks for any help.

void txtTotal_KeyPress(object sender, KeyPressEventArgs e)//when a key is pressed total text box, depending on key add or subtract 1 to another test box (txtTotal is set to read only)
    {


switch (e.KeyChar)
        {                
            case (char)96://numpad 0
                addNRBC();
                break;
      case (char)48://keyboard 0
                subtractNRBC();
                break;
    }

}


 public void addNRBC()
    {
        num1 = Convert.ToInt32(txtNRBC.Text);
        txtNRBC.Text = Convert.ToString(num1 + 1);//adds 1 to NRBCs field
        Total();
    }
    public void subtractNRBC()
    {
        num1 = Convert.ToInt32(txtNRBC.Text);
        txtNRBC.Text = Convert.ToString(num1 - 1);//subtract 1
        Total();
    }

public void Total()//totals all textboxes except NRBCs
    {

        total = int.Parse(txtSegs.Text) + int.Parse(txtLymphs.Text) + int.Parse(txtMonos.Text) + int.Parse(txtBands.Text) + int.Parse(txtEos.Text) + int.Parse(txtBasos.Text) + int.Parse(txtMetas.Text)
                    + int.Parse(txtMyelos.Text) + int.Parse(txtPros.Text) + int.Parse(txtBlasts.Text) + int.Parse(txtPlasmas.Text);
        txtTotal.Text = Convert.ToString(total);

    }

Answer 1

If possible, change your event from KeyPress to KeyDown. This will allow you to use the KeyEventArgs instead of a KeyPressEventArgs and solve your problem, as the latter does not seem to recognize the numpad correctly.

Instead of hardcoding your values, you can also use the Keys enum. It's cleaner than adding a comment.

private void txtTotal_KeyDown(object sender, KeyEventArgs e)
{
    switch (e.KeyCode)
    {
        case Keys.NumPad0:
            addNRBC();
            break;
        case Keys.D0:
            subtractNRBC();
            break;
    }
}