<%@ Page Language="VB" Theme="Default" %>
<%@ Import Namespace="System.IO" %>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Populating TreeView Nodes On-Demand</title>
</head>
<script language="VB" runat="server">
Shared ReadOnly _slashArray() As Char = {"/"}
Sub PopulateNode(ByVal source As Object, ByVal e As TreeNodeEventArgs)
Dim node As TreeNode = e.Node
If (node.Value = "Demos") Then
node.Value = "~/"
End If
Dim rootDirectory As String = Request.MapPath("~/", Request.ApplicationPath, False)
Dim fullPath As String = Request.MapPath(node.Value, Request.ApplicationPath, False)
If (fullPath.StartsWith(rootDirectory) = False) Then
' Mitigate against spoofed callback arguments
' Requested directory is not under root directory
Return
End If
Dim dirs() As String = Directory.GetDirectories(fullPath)
' Enumerate directories
Dim dir As String
For Each dir In dirs
Dim virtualDir As String = node.Value.TrimEnd(_slashArray) & "/" & Path.GetFileName(dir)
Dim newNode As TreeNode = New TreeNode(Path.GetFileName(dir), virtualDir)
If (Directory.GetFiles(dir).Length > 0 _
Or Directory.GetDirectories(dir).Length > 0) Then
newNode.PopulateOnDemand = True
End If
node.ChildNodes.Add(newNode)
Next
' Enumerate files
Dim files() As String = Directory.GetFiles(fullPath)
Dim file As String
For Each file In files
Dim newNode As TreeNode = New TreeNode(Path.GetFileName(file), Path.GetFileName(file))
node.ChildNodes.Add(newNode)
Next
End Sub
</script>
<body>
<div>
<h2>Populating TreeView Nodes On-Demand</h2>
<form action="treeview10_ondemand_vb.aspx" runat="server">
<asp:TreeView Id="MyTree" SkinId="Explorer"
PathSeparator = "|"
OnTreeNodePopulate="PopulateNode"
ExpandDepth="1"
runat="server">
<Nodes>
<asp:TreeNode Text="Demos" PopulateOnDemand="true" />
</Nodes>
</asp:TreeView>
</form>
</div>
</body>
</html>
