UpdatePanel and TreeView problem

I made a couple of changes and your example is working properly now. Here is the code

<%

@.PageLanguage="C#" %>

<%

@.RegisterAssembly="Microsoft.Web.Atlas"Namespace="Microsoft.Web.UI"TagPrefix="atlas" %>

<!

DOCTYPEhtmlPUBLIC"-//W3C//DTD XHTML 1.0 Transitional//EN""http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<

scriptrunat="server">protectedvoid Page_Load(object sender,EventArgs e)

{

}

protectedvoid btn_Click(object sender,EventArgs e)

{

txt1.Text =

DateTime.Now.ToString();

}

protectedvoid tree_TreeNodePopulate(object sender,TreeNodeEventArgs e)

{

TreeNode node =newTreeNode(e.Node.Value +"x", e.Node.Value +"x");

node.PopulateOnDemand =

true;

node.SelectAction =

TreeNodeSelectAction.Expand;

e.Node.ChildNodes.Add(node);

}

</

script>

<

htmlxmlns="http://www.w3.org/1999/xhtml">

<

headrunat="server"><title>Untitled Page</title>

</

head>

<

body><formid="form1"runat="server"><atlas:ScriptManagerID="scriptmanager"EnablePartialRendering="true"runat="Server"/><divstyle="width: 400px; float: left"><atlas:UpdatePanelrunat="server"ID="up1"><ContentTemplate><asp:TreeViewrunat="server"ID="tree"ExpandDepth="1"EnableViewState="true"OnTreeNodePopulate="tree_TreeNodePopulate"><Nodes><asp:TreeNodeValue="1"Text="1"PopulateOnDemand="True"></asp:TreeNode><asp:TreeNodeValue="2"Text="2"PopulateOnDemand="True"></asp:TreeNode></Nodes></asp:TreeView></ContentTemplate></atlas:UpdatePanel></div><div><atlas:UpdatePanelrunat="server"ID="up2"><ContentTemplate><asp:TextBoxrunat="server"ID="txt1"></asp:TextBox><asp:Buttonrunat="server"ID="btn"Text="Button"OnClick="btn_Click"/></ContentTemplate></atlas:UpdatePanel></div><br/></form>

</

body>

</

html>

Hope This helps!

Thanks, it did help me indirectly. My example aspx was somewhat simplified compared to my code, because I was also placing embracing TreeView with user control and creating TreeView dynamically in code-behind. It turned out that I had a line in my TreeViewUserControl.cs inside OnInit:

if (!Page.IsPostBack) buildTreeLevel(treeHierarchy, 0, 0, navigationTree.Nodes,ref ds, AllowAdding,"");

which I used to populate initial nodes. I thought it made sense to populate root of

the tree only in initial page requests and not on postbacks. When I commented out first if line,

it all works fine.

Thanks