HI angel, thnx for your reply, i solve this now, i had one more query. The thing i am selecting mutiple items in a drop down, and i need to take all the selected items and need to pass it to a query.. but after selecting the one time the postback is not happening..i'll send my code to you,please go through that and send me reply .aspx .cs page protected void DD_PropZone_SelectionChanged(object sender, Infragistics.Web.UI.ListControls.DropDownSelectionChangedEventArgs e) { string m="" ; for (int i = 0; i < DD_PropZone.SelectedItems.Count; i++) { m += DD_PropZone.SelectedItems[i].Value.ToString() + "," ; } if (DD_PropZone.SelectedValue != "Select" ) { sSqlQuery = "SELECT DISTINCT City_Locality FROM [City_State_Country_LookUp] WHERE (City_Locality IS NOT NULL OR City_Locality !='') AND City_Zone IN('" + m + "') ORDER BY City_Locality ASC" ; SqlDataAdapter sda91 = new SqlDataAdapter (sSqlQuery, Conn); DataSet ds91 = new DataSet (); sda91.Fill(ds91); dd_Locality.Items.Clear(); dd_Locality.DataSource = ds91.Tables[0]; dd_Locality.DataValueField = "City_Locality" ; dd_Locality.DataTextField = "City_Locality" ; dd_Locality.DataBind(); dd_Locality.Items.Insert(0, "Select" ); } else { BindPageLocality(); } ModalPopupEx_AdSearch.Show(); }