TreeView Control Problem
- by ProgNet
Hi all,
I have a public folder on the server that contains recursively nested sub folders. 
In the various Leaf folders contains Images. 
I wanted to create a server side file browser that will display the Images to the user.
I am using the ASP.NET TreeView Control.
I create the tree nodes using PopulateOnDemand.
If the user click on a leaf directory I want the images in that folder to be displayed in a DataList Control.
The problem is that when I click on a sub tree node (after I expanded it parent node)
All the expanded sub tree disappears and only the parent node is showed with no + sign next to it !!
(  I have set the TreeView's PopulateNodesFromClient property to true )
Can someone tell me what is the problem ??
Thanks
Here is the code :
<asp:TreeView ID="TreeView1" runat="server" AutoGenerateDataBindings="False" 
                    onselectednodechanged="TreeView1_SelectedNodeChanged" 
                    ontreenodepopulate="TreeView1_TreeNodePopulate">
                </asp:TreeView>
protected void Page_Load(object sender, EventArgs e)
{
    if (!Page.IsPostBack)
    {
        string path = Server.MapPath(".");
        PopulateTopNodes(path);
    }
}
private void PopulateTopNodes(string pathToRootFolder)
{
    DirectoryInfo dirInfo = new DirectoryInfo(pathToRootFolder);
    DirectoryInfo[] dirs = dirInfo.GetDirectories();
    foreach (DirectoryInfo dir in dirs)
    {
        TreeNode folderNode = new TreeNode(dir.Name,dir.FullName);
        if (dir.GetDirectories().Length > 0)
        {
            folderNode.PopulateOnDemand = true;
            folderNode.Collapse();
        }
        TreeView1.Nodes.Add(folderNode);
    }
}
protected void TreeView1_TreeNodePopulate(object sender, TreeNodeEventArgs e)
{
    if (IsCallback == true)
    {
        if (e.Node.ChildNodes.Count == 0)
        {
            LoadChildNode(e.Node);
        }
    }
}
private void LoadChildNode(TreeNode treeNode)
{
    DirectoryInfo dirInfo = new DirectoryInfo(treeNode.Value);
    DirectoryInfo[] dirs = dirInfo.GetDirectories();
    foreach (DirectoryInfo dir in dirs)
    {
        TreeNode folderNode = new TreeNode(dir.Name, dir.FullName);
        if(dir.GetDirectories().Length>0){
            folderNode.PopulateOnDemand = true;
            folderNode.Collapse();
        }
        treeNode.ChildNodes.Add(folderNode);
    }
}
protected void TreeView1_SelectedNodeChanged(object sender, EventArgs e)
{
    // Retrieve  the images here 
}