Does anyone have a WORKING example that displays a directory tree structure in a TreeView for VB .NET??

Question

I have looked everywhere and cannot find a version that works. The ones I found are all either outdated or have errors.

I have something that is working for the most part, but I'm having some trouble with restricted-access folders.

The code I'm using is as follows:

Imports System.IO

Public Class frmMain
    Private Sub frmMain_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        For Each drive In DriveInfo.GetDrives
            Dim i As Integer = TreeView1.Nodes.Count

            TreeView1.Nodes.Add(drive.ToString)

            If drive.IsReady Then
                PopulateTree(drive.ToString, TreeView1.Nodes(i))
            End If
        Next
    End Sub

    Private Sub PopulateTree(ByVal sDir As String, ByVal node As TreeNode)
        Dim directory As New DirectoryInfo(sDir)

        Try
            For Each d As DirectoryInfo In directory.GetDirectories
                Dim t As New TreeNode(d.Name)

                PopulateTree(d.FullName, t)
                node.Nodes.Add(t)
            Next
        Catch excpt As UnauthorizedAccessException
            Debug.WriteLine(excpt.Message)
        End Try
    End Sub
End Class

For testing purposes I replaced this section...

If drive.IsReady Then
    PopulateTree(drive.ToString, TreeView1.Nodes(i))
End If

...with this...

If drive.toString = "L:\"
    PopulateTree(drive.ToString, TreeView1.Nodes(i))
End If

...and it worked fine for that drive. The L:\ is a removable USB drive by the way.

However, with the original code I get debug errors on some folders because they are access-restricted. Is there any way to ignore those particular folders and show the rest?

Answer 1

Yes, you need to tighten the scope of your try catch block. You are catching the error too far away from where it occurs. Try this:

Private Sub PopulateTree(ByVal sDir As String, ByVal node As TreeNode)
    Dim directory As New DirectoryInfo(sDir)


        For Each d As DirectoryInfo In directory.GetDirectories
            Dim t As New TreeNode(d.Name)

            Try
               PopulateTree(d.FullName, t)
               node.Nodes.Add(t)
            Catch excpt As UnauthorizedAccessException
               Debug.WriteLine(excpt.Message)
            EndTry
        Next

End Sub