how to render my chart in ddlName_SelectedIndexChanged event

Hi

i can render my visifire chart in page load using asp literal control ...but when i tried to render the chart using literal control

in ddlName_SelectedIndexChanged event chart is not rendering......

like this..


public partial class Kpibystreammember : BasePage
{
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{

this.BindStreammember();

BusinessLogicLayer .Kpibystreammember Kpibystreammember = new BusinessLogicLayer.Kpibystreammember ();
string pid = Session["projid"].ToString();

txtPrjID.Text = this.PrjID.ToString();
this.PopulateForm();

//string graph = Kpibystreammember.ovralKpibystreammember ...