how to select the item in radcombobox based on item value ?

Hi, I am using radcombobox in my project, bind the combo box using page methods see this link.(last method) Working fine to display the items based on loadondemond, but after save the data when i am trying to edit  i am assigning to radcombobox based on item value , but it is not working properly, because radcombobox items are not loaded .  my code is i am trying bellow two ways 1) RadComboBox4.SelectedValue = dr["AgentID"].ToString(); 2) RadComboBox4.FindItemByValue(dr[&qu ...