or
protected void Page_Load(object sender, EventArgs e){ if (!Page.IsPostBack) { UpdateFormWithDBData(); }}<telerik:RadComboBox ID="RadComboState" runat="server" Width="250px" Height="150px" EmptyMessage="Select a state" EnableLoadOnDemand="True" ShowMoreResultsBox="true" EnableVirtualScrolling="true" OnItemsRequested="RadComboState_ItemsRequested"> </telerik:RadComboBox> <telerik:RadComboBox ID="RadComboInstitution" runat="server" Width="250px" Height="150px" EmptyMessage="Select an institution" EnableLoadOnDemand="True" ShowMoreResultsBox="true" EnableVirtualScrolling="true" OnItemsRequested="RadComboInstitution_ItemsRequested" OnClientItemsRequesting="GetSelectedState"> </telerik:RadComboBox>function GetSelectedState(sender, eventArgs) { var SelectedState; var combo = Telerik.Web.UI.RadComboBox.ComboBoxes[0]; SelectedState = combo.get_value(); var context = eventArgs.get_context(); context["StateId"] = SelectedState; } protected void RadComboState_ItemsRequested(object o, RadComboBoxItemsRequestedEventArgs e) { RadComboState.Items.Clear(); DataSet data = PoulateStates(); if (data.Tables.Count > 0 && data.Tables[0].Rows[0][0].ToString() == "0") { int itemOffset = e.NumberOfItems; int endOffset = Math.Min(itemOffset + ItemsPerRequest, data.Tables[0].Rows.Count); e.EndOfItems = endOffset == data.Tables[0].Rows.Count; for (int i = itemOffset; i < endOffset; i++) { RadComboState.Items.Add(new RadComboBoxItem(data.Tables[0].Rows[i]["State_Name"].ToString(), data.Tables[0].Rows[i]["intPkVal"].ToString())); } e.Message = GetStatusMessage(endOffset, data.Tables[0].Rows.Count); } else { RadComboBoxItem item = new RadComboBoxItem(); item.Value = "-1"; if (Session["COUNTRY"] != null && Session["COUNTRY"].ToString().ToUpper() == "MARSHALL ISLANDS") item.Text = "No Island Exists"; else item.Text = "No State Exists"; RadComboState.Items.Add(item); } } protected void RadComboInstitution_ItemsRequested(object o, RadComboBoxItemsRequestedEventArgs e) { RadComboInstitution.Items.Clear(); DataSet Institution = new DataSet(); try { string StateId = e.Context["StateId"].ToString(); Institution = populateInstitution(StateId); if (Institution.Tables[0].Rows[0][0].ToString() == "0") { int itemOffset = e.NumberOfItems; int endOffset = Math.Min(itemOffset + ItemsPerRequest, Institution.Tables[0].Rows.Count); e.EndOfItems = endOffset == Institution.Tables[0].Rows.Count; for (int i = itemOffset; i < endOffset; i++) { RadComboInstitution.Items.Add( new RadComboBoxItem(Institution.Tables[0].Rows[i]["Institution_Name"].ToString(), Institution.Tables[0].Rows[i]["InstitutionId"].ToString())); } e.Message = GetStatusMessage(endOffset, Institution.Tables[0].Rows.Count); } else { RadComboBoxItem item = new RadComboBoxItem(); item.Value = "-1"; item.Text = "No Institution Exists"; RadComboInstitution.Items.Add(item); } } catch (Exception ex) { } }if (e.CommandName == RadGrid.ExportToExcelCommandName)
{ foreach (GridFilteringItem filter in radGrid.MasterTableView.GetItems(GridItemType.FilteringItem)) { filter.Visible = false; } radGrid.MasterTableView.ExportToExcel(); }Unable to serialize the session state. In 'StateServer' and
'SQLServer' mode, ASP.NET will serialize the session state objects, and
as a result non-serializable objects or MarshalByRef objects are not
permitted. The same restriction applies if similar serialization is done
by the custom session state store in 'Custom' mode.

<telerik:RadStyleSheetManager ID="RadStyleSheetManager1" runat="server"></telerik:RadStyleSheetManager><telerik:RadComboBox ID="RadComboBox1" Skin="SilverSkin" EnableEmbeddedSkins="False" runat="server"> <Items> <telerik:RadComboBoxItem runat="server" Text="RadComboBoxItem1" /> <telerik:RadComboBoxItem runat="server" Text="RadComboBoxItem2" /> <telerik:RadComboBoxItem runat="server" Text="RadComboBoxItem3" /> </Items> <CollapseAnimation Type="OutQuint" Duration="200"></CollapseAnimation></telerik:RadComboBox><telerik:RadComboBox ID="RadComboBox2" Skin="Metro" EnableEmbeddedSkins="True" runat="server"> <Items> <telerik:RadComboBoxItem runat="server" Text="RadComboBox2 Item1" /> <telerik:RadComboBoxItem runat="server" Text="RadComboBox2 Item2" /> <telerik:RadComboBoxItem runat="server" Text="RadComboBox2 Item3" /> </Items> <CollapseAnimation Type="OutQuint" Duration="200"></CollapseAnimation></telerik:RadComboBox>// Server Side with RadTreeNode type works fine var node = new RadTreeNode(); node.Attributes.Add("id", "folder_" + dtrReader["folderID"]); // Web Service with RadTreeNodeData type and the DestinationHtmlElement is emptyvar node = new RadTreeNodeData(); node.Attributes.Add("id", "folder_" + dtrReader["folderID"]);