C#: Radio Button doesn't have definition .IsChecked?

Question

I am writing a program to run a testing tool that has two cameras, named Pias and DinoLite. The operator can select which camera is to be active by two radio buttons. I am trying to implement an exception where if an operator tries to select a camera which is not connected, the program will ask if they want to restart with the correct camera installed. If the operator says no, I would like the radio buttons to revert to the previous camera. However, for some reason, the .IsChecked method for radio buttons is not available. Is there a property I must change first? I've seen other posts about using .IsChecked and I couldn't find a similar issue.

Here is my code for the radio button (forgive me if it's appalling, I'm a mechanical engineer by training):

    private void pias_mode_CheckedChanged(object sender, EventArgs e)
    {
        MessageBox.Show("Please ensure the correct camera is installed.  Press OK when finished.", "Camera Switch", MessageBoxButtons.OK);
        if (pias_mode.Checked)
            Mode_Indicator.Text = "Pias Mode";
    }

    private void dino_mode_CheckedChanged_1(object sender, EventArgs e)
    {
        if (dino_mode.Checked)
            Mode_Indicator.Text = "DINO Mode";
            measuringZ = 100;
            try //detects if DinoLite camera is connected
            {
                axDNVideoX1.Connected = true;
                axDNVideoX1.Preview = true;
            }
            catch (Exception)
            {
                DialogResult dialogresult = MessageBox.Show("Could not find DinoLite camera.  Would you like to connect DinoLite camera?  This will require the program to exit.", "Device not Found", MessageBoxButtons.YesNo);
                if (dialogresult == DialogResult.Yes)
                {
                    Close();
                }
                else if (dialogresult == DialogResult.No)
                {
                    pias_mode.IsChecked = true;
                }
            }
    }

Visual studio tells me there is no definition for '.IsChecked'

Here is what it looks like:

Answer 1

You can not change the value of IsChecked. Instead use the Checked property of the RadioButton.