Error Focus RadTreeView !

[uy_2008]

Hi Telerik Team !
I have the follw code :

        protected void radTreeTestCase_NodeExpand(object o, RadTreeNodeEventArgs e)
        {
            // expand node STRQ
            if (e.NodeClicked.Level == 0)
            {
                e.NodeClicked.Nodes.Clear();
                int strqID = Convert.ToInt32(e.NodeClicked.ID);
                ......
                    nodeFEAT.Image = "../Images/Level1.gif";
                    nodeFEAT.ExpandMode = ExpandMode.ServerSide;
                    e.NodeClicked.Nodes.Add(nodeFEAT);                  

                e.NodeClicked.Focus();

                }
            }
.....

And then It occur Error :

Object reference not set to an instance of an object.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error:

Line 1611: e.NodeClicked.Nodes.Add(nodeFEAT); Line 1612: } Line 1613: e.NodeClicked.Focus(); Line 1614: }

Source File: e:\Project EPM\EPM_site\EPM Website\EPM\ProjectInfo\pgTestCase.aspx.cs    Line: 1613

Stack Trace:

[NullReferenceException: Object reference not set to an instance of an object.] System.Web.UI.Control.Focus() +31 EVSOFT.EPM.Web.Project.ProjectInfo_pgTestCase.radTreeTestCase_NodeExpand(Object o, RadTreeNodeEventArgs e) in e:\Project EPM\EPM_site\EPM Website\EPM\ProjectInfo\pgTestCase.aspx.cs:1613 Telerik.WebControls.RadTreeView.OnNodeExpand(RadTreeNodeEventArgs e) +56 Telerik.WebControls.RadTreeView.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String s) +786 System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +32 System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +242 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +3826

---

Version Information: Microsoft .NET Framework Version:2.0.50727.1433; ASP.NET Version:2.0.50727.1433

So I can't user method Focus to focus. So You can explain this error for me and help me  solve with this problem to can focus with Control RadTreeView ?

Thank you verry much !

[Atanas Korchev]

Hi uy_2008 ,

You can use the OnClientNodePopulated event as a workaround:

        <script type="Text/javascript">
       
        function onNodePopulated(sender, args)
        {
            args.get_node().select();
        }
       
        </script>

        <telerik:RadTreeView
            ID="RadTreeView1"
            runat="server"
            Height="300px"
            Width="300px"
            OnNodeExpand="RadTreeView1_NodeExpand"
            OnClientNodePopulated="onNodePopulated"
        />

Regards,
Albert
the Telerik team

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[uy_2008]

Hi Albert !
Thank you about your answer. But your solution it still can't use to solve my problem and can't use method Focus().
So, I have the follow code of .aspx page :

.......
<%@ Register Assembly="RadTreeView.Net2" Namespace="Telerik.WebControls" TagPrefix="radT" %>

.......
 <td valign="top">
                                        <radT:RadTreeView AutoPostBack="True" ID="radTreeTestCase" ShowLineImages="False"
                                            runat="server" DragAndDrop="True" meta:resourcekey="radTRequirementResource1" OnClientNodePopulated="onNodePopulated"
                                            OnNodeClick="radTreeTestCase_NodeClick" MultipleSelect="True" OnNodeDrop="radTreeTestCase_NodeDrop" BeforeClientContextMenu="ShowRadMenu1"
                                            OnNodeContextClick="radTreeTestCase_NodeContextClick" Height="512px" Width="100%">
                                        </radT:RadTreeView>
</td>

...........
And then it can't occur attribute OnNodeExpand with this control, and my error still occur !!!
So, you can help me with this problem?

Thank you again for your whole-hearted help  !

[Atanas Korchev]

Hi uy_2008 ,

You cannot use the Focus method. Please use the workaround mentioned earlier.

Regards,
Albert
the Telerik team

Instantly find answers to your questions at the new Telerik Support Center

[Atanas Korchev]

Hi uy_2008 ,

You seem to be using RadTreeView classic which requires a different approach:

<script type="text/javascript">
    var onDemandNode = false;
   
    function beforeToggle(node)
    {
        if (node.ExpandOnServer == 2)
            onDemandNode = true;
       
        return true;
    }
   
    function afterToggle(node)
    {
        if (onDemandNode)
        {
            node.Select();
            onDemandNode = false;
        }
    }
</script>

<rad:RadTreeView                           
    ID="RadTree1"
    Runat="server"                           
    BeforeClientToggle="beforeToggle"
    AfterClientToggle="afterToggle"
/>

Again you don't need to call the Focus method.

Regards,
Albert
the Telerik team

Instantly find answers to your questions at the new Telerik Support Center

[uy_2008]

Hi Albert !
Thank you very much about your answer. I have tried with your solution, but it can't solve with my problem!!!
I think you misunderstand for my problem. So my problem was: I want to focus to node when i expand it, because sometime my tree have many node (maybe hundreds of nodes on tree), so when i expand it, it doesn't focus to that node and i must scroll to that node again, so now i want to focus to exact that node to easily find it (don't scroll to that node again!!!!).
That's my problem, how to solve with this problem??? You can help me?

Thank you and expect your reply !


P/S: I can't see menu send files to send my code, i very long and big so you can give to me your email to i send to you my code and maybe you see obvious with my problem !!!!


Thank you for all !

[Coldapoy]

yes hi, i dont want to create another thread instead...

i got the same problem though..

how can we achieve this?

many2x thanks team telerik

just me,
coldapoy

[Coldapoy]

its like maintaining scroll position on postback...

[Coldapoy]

team telerik?

[Veselin Vasilev]

Hello Coldapoy,

You can check this KB article:
(ID#419) Scrolling to the selected node


Best wishes,
Veskoni
the Telerik team

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