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Steven
835
Updating WebTree in UpdatePanel through ICallBackEventHandler
posted

I have a tree in an UpdatePanel that through standard event manipulation (i.e., DemandLoad, NodeCollapsed, etc.) works beautifully. I need to update the tree based upon a call through the ICallBackEventHandlerbased upon other actions that occur.

Let me explain further.

My app has 2 frames, 1 containing a WebTree, the other containing a VirtualEarth map.  Data is posted on the map based upon tree selection, and as the map is panned the tree needs to get updated.  Upon completion of the Map panning, I make a call back to the tree frame to update the tree.  In the tree page, I make an ICallBackEventHandler calling the Tree Page  to refresh the tree.

I was doing all this in JavaScript, but Tree manipulation was slow.  Therefore, I'm trying to do on the server.  I want to add / delete nodes from the tree and repost. 

I have an UpdataPanel.Update() (the UpdataPanel UpdateMode is Conditional) at the end of the routine which modifies the tree, but it is not reposting the panel.

Suggestions???  Thanks much!

 

  • 835
    Verified Answer
    posted

    So I research it a bit more and come up with my own answer, as follows:

    1.  No way to do it directly.
    2.  So...Fire and AsynchPostback from Javascript instead ICallBack.  See the following article:   Easily refresh an UpdatePanel, using JavaScript.

    Breaking it down further and varying from the documented workaround, in my Javascript I do a

    __doPostBack("UpdatePanel1", "SetTree::" + params)

    In the PageLoad, I do: 

    strTarget = Request("__EventTarget")
    If Not strTarget Is Nothing AndAlso strTarget.EndsWith("UpdatePanel1") Then
            strRequest = Request("__EventArgument")
            If Not strRequest Is Nothing AndAlso strRequest <> "" Then
            RaiseCallbackEvent(strRequest)
            End If
    End If

    In the RaiseCallbackEvent routine, I make all the necessary changes to the tree and it posts back cleanly and partially.

    This works beautifully!!!