RadGrid.RenderControl(...) Error

[Dave Gasner]

I'm in need of displaying a large amount of data at once to the screen, 1000+ records.  I know that this will take some time, but what I want is that the page will display with the "Loading..." text first, that way the other portions of the page load quickly, and then use a callBack to Render the control.

This works just fine with a GridView, but using the RadGrid it fails.  Any Help would be great.

protected void Page_Load(object sender, EventArgs e)
{
    if (!Page.IsPostBack)
    {
        ......
        ......
        ......

        ltCallbackAttributeGrid.Text = ClientScript.GetCallbackEventReference(this,
            "'bindAttr'", "EndGetData2", "'asyncgrid2'", false);
    }
}

#region ICallbackEventHandler Members
    private string _callBack;

    public string GetCallbackResult()
    {
        return _callBack;
    }

    public void RaiseCallbackEvent(string eventArgument)
    {
        grdAttributes.DataSource = _additionalAttributeColumns;
        grdAttributes.DataBind();

        using (StringWriter sw = new StringWriter())
        {
            grdAttributes.RenderControl(new HtmlTextWriter(sw));
            _callBack = sw.ToString();
        }
    }
#endregion

<div id="attributeGridDiv">
    <telerik:RadGrid runat="server" ID="grdAttributes" AutoGenerateColumns="false"
        BorderWidth="0" Skin="Office2007" GridLines="None" >
        <MasterTableView>
            <Columns>
                <telerik:GridTemplateColumn UniqueName="chkbxSelect">
                    <ItemTemplate>
                        <asp:CheckBox runat="server" ID="chkbxAttributeSelect" AutoPostBack="true" OnCheckedChanged="chkbxAttributeSelect_CheckedChanged" />
                    </ItemTemplate>
                </telerik:GridTemplateColumn>
                <telerik:GridBoundColumn UniqueName="Name" DataField="string_Text" HeaderText="Name" DataType="System.String" />
            </Columns>
        </MasterTableView>
    </telerik:RadGrid>
</div>
<script type="text/javascript">
    function EndGetData2(arg)
    {
        document.getElementById("attributeGridDiv").innerHTML = arg;
    }

    setTimeout("<asp:literal runat='server' id='ltCallbackAttributeGrid' />", 3000);
</script>

Thanks in Advance
Davey

[Yavor]

Hi Dave,

Rendering the control like this, and binding it in such a manner will break its functionalities, since using DataBind() for the control implies simple databinding. A more suitable approach in this case would be to hide the grid while it is loading, and during that time display a loading panel. When the grid has finished rendering, you can hide the panel and show the grid.
I hope this suggestion helps.

Sincerely yours,
Yavor
the Telerik team

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