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Using Telerik AJAX in SharePoint WebParts

When using Ajax in SharePoint WebParts we recommend to add RadAjaxManager programmatically.

This should be done in the OnInit event of the Web Part

You should then add the ajax settings in CreateChildControls.

Here is a short example of what the code-behind can look in this case:

How to use RadAjax in SharePoint Web Parts

public class WebPart1 : WebPart
{
    RadAjaxManager ajaxmgr;
    protected override void OnInit(EventArgs e)
    {
        base.OnInit(e);
        ajaxmgr = RadAjaxManager.GetCurrent(Page);
        if (ajaxmgr == null)
        {
            ajaxmgr = new RadAjaxManager() { ID = "RadAjaxManager1" };
            Page.Items.Add(typeof(RadAjaxManager), ajaxmgr);
        }

        if (Page.Form != null)
        {
            Page.Form.Controls.AddAt(0, ajaxmgr);
        }
        EnsureChildControls();
    }

    protected override void CreateChildControls()
    {
        //create RadGrid, AjaxManager and any other necessary controls here

          RadGrid grid = FindControl("RadGrid1") as RadGrid;
          RadAjaxLoadingPanel loadingPanel =            FindControl("RadAjaxLoadingPanel1") as RadAjaxLoadingPanel;
        //add necessary ajax settings
        if (ajaxmgr != null)
        {
            AjaxSetting ajaxSetting = new AjaxSetting();

            ajaxSetting.AjaxControlID = grid.ID;
            ajaxSetting.UpdatedControls.Add(new AjaxUpdatedControl(grid.ID, loadingPanel.ID));

            ajaxmgr.AjaxSettings.Add(ajaxSetting);
        }
    }
}



Public Class WebPart1
    Inherits WebPart
    Private ajaxmgr As RadAjaxManager
    Protected Overrides Sub OnInit(e As EventArgs)
        MyBase.OnInit(e)
        ajaxmgr = RadAjaxManager.GetCurrent(Page)
        If ajaxmgr Is Nothing Then
            ajaxmgr = New RadAjaxManager() With { _
                Key .ID = "RadAjaxManager1" _
            }
            Page.Items.Add(GetType(RadAjaxManager), ajaxmgr)
        End If

        If Page.Form IsNot Nothing Then
            Page.Form.Controls.AddAt(0, ajaxmgr)
        End If
        EnsureChildControls()
    End Sub

    Protected Overrides Sub CreateChildControls()
        'create RadGrid, AjaxManager and any other necessary controls here

        Dim grid As RadGrid = TryCast(FindControl("RadGrid1"), RadGrid)
        Dim loadingPanel As RadAjaxLoadingPanel = TryCast(FindControl("RadAjaxLoadingPanel1"), RadAjaxLoadingPanel)
        'add necessary ajax settings
        If ajaxmgr IsNot Nothing Then
            Dim ajaxSetting As New AjaxSetting()

            ajaxSetting.AjaxControlID = grid.ID
            ajaxSetting.UpdatedControls.Add(New AjaxUpdatedControl(grid.ID, loadingPanel.ID))

            ajaxmgr.AjaxSettings.Add(ajaxSetting)
        End If
    End Sub
End Class

Troubleshooting

Avoid using two different methods of AJAX-enabling content. For example, if you use the approach above, do not use RadAjaxPanel or asp:UpdatePanel for the same content.

RadAjaxPanel cannot be guaranteed to work as expected under SharePoint.

Make sure there are no JavaScript errors or invalid markup on the page. Either of these issues tends to break AJAX requests.

If you get the following error:

The control collection cannot be modified during DataBind, Init, Load, PreRender or Unload phases

you can try these options:

  • Move the SharePoint Web Part Manager from the header to the body, or after the script manager. Here is an example of what you should look for:

    Markup

    <SharePoint:AjaxDelta id="DeltaSPWebPartManager" runat="server">
        <WebPartPages:SPWebPartManager runat="server">
        </WebPartPages:SPWebPartManager>
    </SharePoint:AjaxDelta>
    
  • Use only asp:UpdatePanel and asp:UpdateProgress controls to AJAX-enable the content, without using RadAjax.