Home / Community & Support / Code Library / ASP.NET AJAX > General and Integration Projects > Page-level property to detect an Ajax callback

• Milan Negovan

  Posted on Jun 12, 2006 (permalink)

  Requirements
  r.a.d.controls version	Any Telerik control
  .NET version	2.0
  Visual Studio version	2003/2005
  programming language	C#
  browser support	all browsers supported by r.a.d.controls

  Sometimes I need to know if a page is going through a normal postback or a callback. Although Rad controls have a property for this, IsCallback, I prefer a page property which does not get involved with any control directly.
  
  Simply add the following property to your page base class:
  
  public bool IsAjaxCallback
  {
      get
      {
          HttpContext ctx = HttpContext.Current;

          return (
               ctx != null &&
               ctx .Request != null &&
              (ctx.Request.QueryString["rcbID"] != null || ctx.Request.Form["ctrlid"] != null));
      }
  }
  

  Reply

• Steve Steve

  Posted on Jun 13, 2006 (permalink)

  Hi Milan,
  
  Thank you for posting this demo application in our code library section. However can you please send us a sample project corresponding to the solution presented here. This is the main idea behind the code-library, so people can download a sample and see if it works as they expect.

  We appreciate your involvement!
  
  Kind regards,

  Steve
  the telerik team

  
  www.telerik.com | dnn.telerik.com | www.sharepointcontrols.com | www.sitefinity.com | www.mcmscontrols.com

  Reply

• Dan Avni

  Posted on Jun 14, 2006 (permalink)

  the code you suggested does not take into account other callbacks like the grid or treeview callbacks. i think this approach is better because it does not care about the posted data so if telerik changes the name of the parameter in the query string my code would still run
  
          Public ReadOnly Property IsAjaxCallback() As Boolean
              Get
                  Return IsAjaxCallbackRecursive(Me.Controls)
              End Get
          End Property
          Private Function IsAjaxCallbackRecursive(ByVal ContainedControls As System.Web.UI.ControlCollection) As Boolean
              For Each Ctl As System.Web.UI.Control In ContainedControls
                  If TypeOf Ctl Is Telerik.WebControls.CallbackControls.ICallbackControl Then
                      Dim CBProps As Telerik.WebControls.CallbackControls.ICallbackControl = CType(Ctl, Telerik.WebControls.CallbackControls.ICallbackControl)
                      If CBProps.IsCallback Then Return True
                  ElseIf TypeOf Ctl Is Telerik.WebControls.RadComboBox Then
                      If CType(Ctl, Telerik.WebControls.RadComboBox).IsCallBack Then Return True
                  ElseIf TypeOf Ctl Is Telerik.WebControls.RadGrid Then
                      If CType(Ctl, Telerik.WebControls.RadGrid).IsAsyncRequest Then Return True
                  ElseIf TypeOf Ctl Is Telerik.WebControls.RadTreeView Then
                      If CType(Ctl, Telerik.WebControls.RadTreeView).IsCallBack Then Return True
                  End If
                  'run recursive
                  If Ctl.Controls.Count > 0 Then
                      If IsAjaxCallbackRecursive(Ctl.Controls) Then
                          Return True
                      End If
                  End If
              Next
          End Function
  

  Reply

• JohnC

  Posted on Sep 18, 2006 (permalink)

  Thank you Milan, exactly what I was looking for.  I can't imagine why there isn't some built in method or property in the RadManger to detect this on page load.
  
  Cheers!
  
  P.S. for the record this is what worked for me using just RadAjaxManager on a form:
  
  

  ctx.Request.Form["RadAJAXControlID"]!=null

  Reply

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