System.Collections.ArrayList listRdoBtn = new System.Collections.ArrayList();
...
System.Windows.Forms.RadioButton rdo1 = new System.Windows.Forms.RadioButton();
rdo1.Text = "radio button1";
rdo1.CheckedChanged += new EventHandler(rdo1_CheckedChanged);
listRdoBtn.Add(rdo1);
System.Windows.Forms.RadioButton rdo2 = new System.Windows.Forms.RadioButton();
rdo2.Text = "radio button2";
rdo2.CheckedChanged += new EventHandler(rdo2_CheckedChanged);
listRdoBtn.Add(rdo2);
System.Windows.Forms.RadioButton rdo3 = new System.Windows.Forms.RadioButton();
rdo3.Text = "radio button3";
rdo3.CheckedChanged += new EventHandler(rdo3_CheckedChanged);
listRdoBtn.Add(rdo3);
private void rdo1_CheckedChanged(object sender, EventArgs e)
{
string strText = ((System.Windows.Forms.RadioButton)sender).Text;
// Show text in the text editor...
// ...
}