OnAjaxUpdate Error in Tooltip RadGrid

[Pei Chen]

I basically want to use the Tool / ToolTipified Grid from the Telerik, I followed pretty much the same instructions with a bit of differences in ascx.  But it gave me the error:

RadToolTipManager response error:
Exception=Sys.WebForms.PageRequetManagerServerErrorException: Object reference not set to an instance of an object.

And the tooltip fires but content is not populated.

Below are my codes:

Default.aspx

<telerik:RadAjaxPanel runat="server" ID="AjaxPanel">

         <telerik:RadGrid  ID="RadGrid1" runat="server" AllowMultiRowSelection="true"
                AllowSorting="True" AutoGenerateColumns="False" GridLines="Both"
                Skin="Black" SelectedItemStyle-ForeColor="Aqua" OnSortCommand="RadGrid1_SortCommand">
             <MasterTableView  ClientDataKeyNames="NodeName" RowIndicatorColumn-Display="false" TableLayout="Auto" AllowMultiColumnSorting="true" DataKeyNames="NodeName"    >
             <Columns>

            <telerik:GridBoundColumn HeaderText="Terminal" DataField="NodeName" SortExpression="NodeName" ItemStyle-Wrap="false"
                     ItemStyle-HorizontalAlign="Center" UniqueName="DisplayName">
                <ItemStyle HorizontalAlign="Left" Wrap="False" />
                 </telerik:GridBoundColumn>
            <telerik:GridBoundColumn HeaderText="IP Address" DataField="IPAddress" SortExpression="IPAddress" ItemStyle-Wrap="false"
                     ItemStyle-HorizontalAlign="Center" UniqueName="IpAddress" HeaderStyle-HorizontalAlign="Center" AllowSorting="false" >
                 </telerik:GridBoundColumn>

                       <telerik:GridBoundColumn HeaderText="Last Online Time" SortExpression="LastOnline"  ItemStyle-Wrap="false" ItemStyle-HorizontalAlign="Center" UniqueName="LastOnlineTime" HeaderStyle-HorizontalAlign="Center" AllowSorting="false" >
                 </telerik:GridBoundColumn>

                  <telerik:GridTemplateColumn HeaderText="Product" SortExpression="ProductName">
                    <ItemTemplate>
                        <asp:HyperLink ID="targetControl" runat="server" NavigateUrl="#"><img src="Style/Images/page2.gif" border="0" /></asp:HyperLink>
                    </ItemTemplate>
                </telerik:GridTemplateColumn>


             </Columns>
             <RowIndicatorColumn>
                        <HeaderStyle Width="20px" />
                    </RowIndicatorColumn>
                    <ExpandCollapseColumn>
                        <HeaderStyle Width="20px" />
                    </ExpandCollapseColumn>
                </MasterTableView>
                <ClientSettings EnableRowHoverStyle="true" >  <Selecting AllowRowSelect="true"/>

                  <ClientEvents OnRowCreated="RadGrid1_RowCreated" OnRowDeSelected="RadGrid1_RowDeselected" OnRowSelected="RadGrid1_RowSelected" OnRowContextMenu="RowContextMenu" />

                    </ClientSettings>

                 </telerik:RadGrid>




   <asp:Timer ID="Timer1" runat="server" EnableViewState="False" Interval="500000" OnTick="Timer1_Tick">
        </asp:Timer>

     </telerik:RadAjaxPanel>




    <telerik:RadAjaxManager ID="RadAjaxManager2" runat="server" DefaultLoadingPanelID="RadAjaxLoadingPanel1">
       <AjaxSettings>
           <telerik:AjaxSetting AjaxControlID="Timer1">
               <UpdatedControls>
                   <telerik:AjaxUpdatedControl ControlID="AjaxPanel" />
               </UpdatedControls>
               <UpdatedControls>
                    <telerik:AjaxUpdatedControl ControlID="RadGrid1" LoadingPanelID="RadAjaxLoadingPanel1" />
                    <telerik:AjaxUpdatedControl ControlID="RadToolTipManager1" />
                </UpdatedControls>

           </telerik:AjaxSetting>
       </AjaxSettings>
    </telerik:RadAjaxManager>

    <telerik:RadToolTipManager ID="RadToolTipManager1" OffsetY="-1" HideEvent="ManualClose"
        Width="250" Height="350" runat="server"  RelativeTo="Element"  OnAjaxUpdate="OnAjaxUpdate"
        Position="MiddleRight" >
    </telerik:RadToolTipManager>


    <telerik:RadAjaxLoadingPanel ID="RadAjaxLoadingPanel1" runat="server" Transparency="30" CssClass="LoadingPanel" >
    </telerik:RadAjaxLoadingPanel>

Default.aspx.vb

    Private Sub UpdateToolTip(ByVal elementID As String, ByVal panel As UpdatePanel)
        Dim ctrl As Control = Page.LoadControl("ctrlGridRowDetail.ascx")
        panel.ContentTemplateContainer.Controls.Add(ctrl)
        Dim details As ctrlGridRowDetail = DirectCast(ctrl, ctrlGridRowDetail)
        details.rowID = elementID
    End Sub

    Sub OnAjaxUpdate(ByVal sender As Object, ByVal args As ToolTipUpdateEventArgs)
        Me.UpdateToolTip(args.Value, args.UpdatePanel)
    End Sub

 Private Sub RadGrid1_ItemDataBound(ByVal sender As Object, ByVal e As Telerik.Web.UI.GridItemEventArgs) Handles RadGrid1.ItemDataBound
        If (TypeOf (e.Item) Is GridDataItem) Then


            Dim target As Control = e.Item.FindControl("targetControl")
            If Not [Object].Equals(target, Nothing) Then
                If Not [Object].Equals(Me.RadToolTipManager1, Nothing) Then

                    Me.RadToolTipManager1.TargetControls.Add(target.ClientID, (TryCast(e.Item, GridDataItem)).GetDataKeyValue("NodeName").ToString(), True)

                End If
            End If


        End If


    End Sub

 Protected Sub RadGrid1_SortCommand(ByVal source As Object, ByVal e As Telerik.Web.UI.GridSortCommandEventArgs)
        RadToolTipManager1.TargetControls.Clear()
End Sub

Controls

<%@ Control Language="vb" AutoEventWireup="false" CodeBehind="ctrlGridRowDetail.ascx.vb" Inherits="ClientWebApp.ctrlGridRowDetail" %>

  <asp:Label runat="server" ID="lblTitle"></asp:Label>
  <asp:Label ID="lblAttribute" runat="server"></asp:Label>

 Private row As String

    Property rowID() As String
        Get
            Return row
        End Get
        Set(ByVal value As String)
            row = value
        End Set
    End Property


    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
                 BindNodeInfo()

    End Sub

    Protected Sub BindNodeInfo()
                 <<-- Populate Data here and attach result to a string builder -->
                lblAttribute.Text = sb.ToString()
    End Sub

[Svetlina Anati]

Hello Pei,

The code snippet you have pasted seems to be correct. What I can suggest is to first remove all the ajax settings and set debug="true" in the Web.config. This will show what causes the server error and you will be able to see which exact element is null. After that you can set a breakpoint and debug the server code.

Sincerely yours,
Svetlina
the Telerik team

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