public bool Checked {get; set;}

public void CreateMyGcRadioGroupBox()
{
    GcRadioGroupBox gcRadioGroupBox1 = new GcRadioGroupBox();
    gcRadioGroupBox1.Location = new Point(15, 15);
    gcRadioGroupBox1.Text = "MyGcRadioGroupBox";

    // Create an item.
    RadioButtonItem item = new RadioButtonItem();

    // Set the Text of RadioButtonItem.
    item.Text = "MyRadioButtonItem";

    // Set a new Font from the existing font.
    item.Font = new Font(item.Font, FontStyle.Bold);

    // Set the BackColor and ForeColor properties for RadioButtonItem.
    item.BackColor = Color.LightGreen;
    item.ForeColor = Color.LightPink;

    // Disable the item.
    item.Enabled = false;

    gcRadioGroupBox1.LayoutSettings.LayoutMode = LayoutMode.Absolute;
    // Set the location of the item.
    item.Location = new Point(15, 15);

    // Clone an item, modify its location and change its Enabled to true to enable the UI interaction.
    RadioButtonItem clonedItem = item.Clone() as RadioButtonItem;
    clonedItem.Location = new Point(15, 40);
    clonedItem.Enabled = true;

    gcRadioGroupBox1.Items.Add(item);
    gcRadioGroupBox1.Items.Add(clonedItem);
    this.Controls.Add(gcRadioGroupBox1);
}