Treeview in Updatepanels in ASP2

Question

I have a problem with expanding/collapsing a Treeview control in an Updatepanel which causes weird behavior and functions fine if placed outside the Updatepanel.

I have found that TreeViews is not supported in updatePanels so my question is:

• What is a workaround to avoid a full postback whilst keeping expand/collapse functionality as well as TreeNode_clicks that updates another control?
• Also why does it seem that some people use a TreeView inside an Updatepanel with success? Is this only an ASP2 prolbem?

Answer 1

TreeView in .Net 2.0 doesn't need to postback on expand/collapse.

Have you tried to put an UpdatePanel around the control you wish to update with a trigger

< asp:PostBackTrigger ControlID="treeView" />

Answer 2

It's the loading of the treeview javascript that fails under an updatepanel. I've tried putting some explanations and options below in bullet points.

• The control will work in an updatepanel if it is visible straight away.
• The control will not work in an updatepanel if it is made visible after a postback.
• If you disable the client side javascript, the control will work in an updatepanel but will cause a postback every time a plus/minus is clicked.

Hope that helps

Answer 3

As declared by Microsoft, treeview is not compatible with UpdatePanel. So you are having all the issues. I have managed the same to a quite acceptable level in one of my project. You can refer to the posts on the same as follows: http://www.geekays.net/post/Using-TreeView-inside-AJAX-UpdatePanel.aspx and http://www.geekays.net/post/TreeView-control-postbacks-on-check-and-uncheck-of-the-nodes-Checkbox.aspx

Let me know if it helps.