How to assign the multiple values in MultiCombo

[krishna]

below the code i m using but its giveing the clientconfig Error in of system.collection
ArrayList arr = new ArrayList();
foreach (SelectedListItem lstInsurance in ddlPhysicianN.SelectedItems)
{
Session["PhysicianID"] = lstInsurance.Value;
arr.Add(lstInsurance.Value);
}
Session["PhySelected"] = arr;


ArrayList arr = (ArrayList)Session["PhySelected"];
if (arr.Count > 0)
{
ddlPhysicianN.SetValue(arr);
}


1)how to assign the multi values form a muticombo without arralist
2) how to set the multi check value to multicombo.

pls reply me as soon as possible...

[krishna]

pls help me...