TreeView Explorer using VB.NET 2008

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• Download MBTreeViewExplorer_Article.zip - 650.8 KB

Introduction

What is the MBTreeViewExplorer? This is a simple TreeView derived control which uses the Windows Explorer interface. It provides no added functionality aside from the standard TreeView control methods, properties, and events, however it does provide a Shell Item class, which can be used to extend this basic example for your own needs, and it is also a good starting point for those wanting to get to grips with the system image list and Shell32 programming.

Background

MBTreeViewExplorer is an explorer which inherits all the properties of simple TreeView control. The language used is VB.NET. Parts of the code are based on other CodeProject tutorials and code samples found elsewhere on the Internet. All of the code was written by me but some of the concepts are from other references and books.

What I think is best about this program:

1. It is a simple design, which should help you to learn how to use the TreeView control.
2. Compared with many of the other sample or demo programs available, it loads directories fast!
3. The program only loads the necessary folders.
4. Here are only two events, and one method which drives the MBTreeViewExplorer control.

Code

The concept for this MBTreeViewExplorer came from the Windows Explorer. MBTreeViewExplorer consists of four classes, ShellAPI, Shell Item, ShellDLL and SystemImageList. I organized methods of MBTreeViewExplorer into layers like this:

The following method loads all Folder Nodes for MBTreeViewExplorer:

Private Sub LoadNodes()
       'Set Treeview Image List for MBTreeViewExplorer
        SystemImageList.SetTreeViewImageList(MBTreeView, False)
        'New ShellItem to Load Desktop
        Dim m_shDesktop As ShellItem = New ShellItem()
        Dim tvwRoot As TreeNode = New TreeNode()
        tvwRoot.Name = m_shDesktop.Path
        tvwRoot.Text = m_shDesktop.DisplayName
        tvwRoot.ImageIndex = m_shDesktop.IconIndexNormal
        tvwRoot.SelectedImageIndex = m_shDesktop.IconIndexOpen
        tvwRoot.Tag = m_shDesktop

        Dim arrChildren As ArrayList = m_shDesktop.GetAllDirectories
        For Each shChild As ShellItem In arrChildren
            Dim tvwChild As TreeNode = New TreeNode()
            tvwChild.Name = shChild.Path
            tvwChild.Text = shChild.DisplayName
            tvwChild.ImageIndex = shChild.IconIndexNormal
            tvwChild.SelectedImageIndex = shChild.IconIndexOpen
            tvwChild.Tag = shChild
            If shChild.IsFolder And shChild.HasSubFolders Then tvwChild.Nodes.Add("PH")
            tvwRoot.Nodes.Add(tvwChild)
        Next
        MBTreeView.Nodes.Clear()
        MBTreeView.Nodes.Add(tvwRoot)
        tvwRoot.Expand() End Sub

The following method handles Icons for MBTreeViewExplorer:

Public Shared Sub SetTreeViewImageList( _
        ByVal treeView As TreeView, _
        ByVal forStateImages As Boolean)
        Initializer()
        Dim wParam As Integer = LVSIL_NORMAL
        If forStateImages Then
            wParam = LVSIL_STATE
        End If
        Dim HR As Integer
        HR = SendMessage(treeView.Handle, _
                    TVM_SETIMAGELIST, _
                    wParam, _
                    m_smImgList)
End Sub

Using the Code

It is very easy to use the MBTreeViewExplorer in your application. Simply add the reference of the provided DLL to your application and just drag and drop.

History

• MBTreeViewExplorer Version 1.0