Question

I’ve got an event handler that is shared by all of my radiobuttons:

private void radioButtonPackers_CheckedChanged(object sender, EventArgs e)
{
    var rb = sender as RadioButton;
    if (rb == radioButtonPackers)
    {
        team = NFCNorth.Packers;
    } else if (rb == radioButtonBears)
    {
        team = NFCNorth.Bears;
    } else if . . .
}

rb is always seen as being radioButtonPackers, even after I’ve checked the radioButtonBears, radioButtonVikings, or radioButtonLions radiobutton.

Do I have to do something like:

if (radioButtonPackers.Checked)
{
    team = NFCNorth.Packers;
}
else if (radioButtonBears.Checked)
{
    team = NFCNorth.Bears;
}
. . .

?

Answer 1

You need to take note of rb.Checked, but in my experience you’ll get an “unchecked” event before you get the “checked” one anyway. Here’s a short but complete example which works:

using System;
using System.Windows.Forms;

class Program
{
    public static void Main()
    {
        var b1 = new RadioButton { Text = "Button 1" };
        var b2 = new RadioButton { Text = "Button 2" };

        EventHandler handler = (sender, args) => {
            RadioButton button = (RadioButton) sender;
            Console.WriteLine("{0} {1}",
                button.Text,
                button.Checked ? "Checked" : "Unchecked");
        };

        b1.CheckedChanged += handler;
        b2.CheckedChanged += handler;

        var form = new Form {
            Controls = {
                new FlowLayoutPanel {
                    FlowDirection = FlowDirection.TopDown,
                    Controls = { b1, b2 }
                }
            }
        };
        Application.Run(form);
    }    
}

If you click on Button 1 then on Button 2, you’ll see:

Button 1 Checked    
Button 1 Unchecked    
Button 2 Checked