Radio button list dynamic Events not working

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C#

i have added a Radiobuttonlist control dynamically and added a event for that control
but the method is not calling

here the code

RadioButtonList rdolst = new RadioButtonList();
                        rdolst.ID = Qno;
                        rdolst.RepeatDirection = rep;
                        rdolst.Items.Add("A");
                        rdolst.Items.Add("B");
                        rdolst.Items.Add("C");
                        rdolst.Items.Add("D");
   rdolst.SelectedIndexChanged += new EventHandler(ddl_SelectedIndexChanged);

after i have added the method

public void ddl_SelectedIndexChanged(object sender, System.EventArgs e)
        {
            RadioButtonList rdoAns = (RadioButtonList)sender;
            string vlistindex = Convert.ToString(rdoAns.ID).Substring(6);
        }

this method is not calling

please help me :(