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Error callbackpanel and treeview-Control

Thread ID:





67333 Aug 14,2007 01:31 PM UTC Aug 21,2007 12:57 PM UTC ASP.NET Web Forms (Classic) 2
Tags: Tools
Mr. Sascha Wald
Asked On August 14, 2007 01:31 PM UTC

Hi there,

using 5.1.1 I have a page with a GridGroupingControl an a callbackpanel. In this callback-panel I have a placeholdercontrol.

When the user select an Item (Hyperlink) in the Grid, the placeholder is filled with the corresponding control (only 1, e.g. a textbox, a listbox...). this works great, except with the syncfusion treeview.

I used your "Load On Demand" example (Toolsweb) to prepare the treeview, but get an error:
"Microsoft JScript runtime error: 'hdnField' is null or not an object"

here is some code:

Dim parameterTree As New Syncfusion.Web.UI.WebControls.Tools.TreeView

Dim parameterControl As New Control
parameterTree = CreateTreeView() '--> from your example
parameterTree.EnableCallbacks = True
parameterControl = CType(parameterTree, Control)
ParameterPlaceHolder.Controls.Add(parameterControl) '--> crash

If I am using the treeview-Control outside the placeholder, everything works fine. The problem there is, that visibility is not switched, so the treeview-control is visible all the time...

any suggestions?


Sascha Wald
Replied On August 16, 2007 03:35 PM UTC


after these tremendous count of possible causes I tried today to build a workaround:
I generated via code a genericdropdown in the callback-panel-refresh-procedure: the control was shown successfully.
Next i tried to add a treeviewcontrol into this genericdropdown, added some nodes via code -> error "Microsoft JScript runtime error: 'hdnField' is null or not an object".
Next I tried same procedure without adding nodes. --> same crash.

what now? Please send me a hint.

regards sascha

Melba Winshia [Syncfusion]
Replied On August 21, 2007 12:57 PM UTC

Hi Sascha,

Thank you for posting your query to us.

I am afraid that I was not able to reproduce the issue. Please refer to the following steps that I tried to reproduce it.

1. Created a sample with callback panel and genericdropdown
2. Then added a treeviewcontrol into this genericdropdown
3. Added some nodes in the callback-panel-refresh-procedure
4. Run the sample
5. No issues.

Also I have created a simple sample to test this issue and it is available in the following link.


Please have a look at the above sample and if still the issue exists, could you please try reproducing it in the above sample or send us the reproducing steps so that we could sort out the cause of the issue and provide you a solution?



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