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Using ImageList in Custom TreeView Control

I am creating a custom control in Visual Basic 2008 that inherits the TreeView control. I added an ImageList control from the toolbox and inserted 6 images for various drives and folders.

The control will display a folder hierarchy based on the path given.

My problem is when I add the control to a form and run it the images do not appear for the nodes.

Am I missing something?

Here is the relevant code, I think, if that helps:

Imports System
Imports System.Windows.Forms
Imports System.Drawing
Imports System.ComponentModel
Imports System.IO
Imports System.Runtime.InteropServices

Public Class asDirectoryViewer

Inherits TreeView

Private components As System.ComponentModel.IContainer

' .... My Properties and Functions

Private Sub InitializeComponent()
Me.components = New System.ComponentModel.Container
Dim resources As System.ComponentModel.ComponentResourceManager = New System.ComponentModel.ComponentResourceManager(GetType(asDirectoryViewer))
Me.imlDriveTree = New System.Windows.Forms.ImageList(Me.components)
Me.SuspendLayout()
'
'imlDriveTree
'
Me.imlDriveTree.ImageStream = CType(resources.GetObject("imlDriveTree.ImageStream"), System.Windows.Forms.ImageListStreamer)
Me.imlDriveTree.TransparentColor = System.Drawing.Color.Transparent
Me.imlDriveTree.Images.SetKeyName(0, "Network_Drive.ico")
Me.imlDriveTree.Images.SetKeyName(1, "HardDrive.ico")
Me.imlDriveTree.Images.SetKeyName(2, "disc drive.ico")
Me.imlDriveTree.Images.SetKeyName(3, "Removable.ico")
Me.imlDriveTree.Images.SetKeyName(4, "Folder.ico")
Me.imlDriveTree.Images.SetKeyName(5, "Open.ico")
'
'asDirectoryViewer
'
Me.ImageList = imlDriveTree
'
Me.ResumeLayout(False)

End Sub

Protected Overrides Sub Finalize()
Me.Nodes.Clear()
MyBase.Nodes.Clear()
MyBase.Finalize()
End Sub

End Class

I can't figure out why the images for the nodes are not showing up at runtime.

Thanks,

Terry

Nasir Razzaq

Where are you setting the images?

Try this example

http://www.codeproject.com/KB/tree/FileSystemTreeView.aspx

kingman1

ASKER

I added the images to the ImageList using the Collections dialog in the ImageLists property window. I want the images compiled with the control so the user does not have to supply them.

Nasir Razzaq

But you need to assign the images to the nodes as well. Just adding the images to the image list wont work.

kingman1

ASKER

In the InitializeComponent sub I set the controls imagelist property to the imagelist.

Here is the code that adds the nodes and sets the images: in this case 4 and 5

Private Sub AddAllFolders(ByVal TNode As TreeNode, ByVal FolderPath As String)
        Try
            For Each FolderNode As String In Directory.GetDirectories(FolderPath)
                Dim SubFolderNode As TreeNode = TNode.Nodes.Add(FolderNode.Substring(FolderNode.LastIndexOf("\"c) + 1), FolderNode.Substring(FolderNode.LastIndexOf("\"c) + 1), 4, 5)

                If FolderNode.EndsWith("\") Then
                    SubFolderNode.Tag = FolderNode
                Else
                    SubFolderNode.Tag = FolderNode & "\"
                End If

                SubFolderNode.Nodes.Add("Loading...")
            Next
        Catch ex As Exception
            MessageBox.Show(ex.Message, "Folder TreeView", MessageBoxButtons.OK, MessageBoxIcon.Error)
        End Try

    End Sub

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Nasir Razzaq

Along with setting the ImageList property of the tree, you need to set the ImageIndex property of each node.

SubFolderNode.ImageIndex = 2

http://msdn.microsoft.com/en-us/library/system.windows.forms.treenode.imageindex.aspx

kingman1

ASKER

OK I updated my code as follows but it still does not show the images.

Private Sub AddAllFolders(ByVal TNode As TreeNode, ByVal FolderPath As String)
        Try
            For Each FolderNode As String In Directory.GetDirectories(FolderPath)
                Dim SubFolderNode As TreeNode = TNode.Nodes.Add(FolderNode.Substring(FolderNode.LastIndexOf("\"c) + 1), FolderNode.Substring(FolderNode.LastIndexOf("\"c) + 1), 4, 5)

                If FolderNode.EndsWith("\") Then
                    SubFolderNode.Tag = FolderNode
                Else
                    SubFolderNode.Tag = FolderNode & "\"
                End If

                SubFolderNode.Nodes.Add("Loading...")
                SubFolderNode.ImageIndex = 4
                SubFolderNode.SelectedImageIndex = 5
            Next
        Catch ex As Exception
            MessageBox.Show(ex.Message, "Folder TreeView", MessageBoxButtons.OK, MessageBoxIcon.Error)
        End Try

    End Sub

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Nasir Razzaq

In your original code, you only have SetKeyName method calls for the imagelist. Do you actually add images in the image list? Are you able to see the images in the list in designer? Attach a screenshot.

kingman1

ASKER

Yes, I added the images to the imagelist. The code below was automatically inserted by Visual Studio. I did not add it. I have also attached the requested screen shot.

Sorry for all the trouble. I really do appreciate the help. I am new to control programming in .net, this is my first attempt at creating a custom control.

Me.imlDriveTree.ImageStream = CType(resources.GetObject("imlDriveTree.ImageStream"), System.Windows.Forms.ImageListStreamer)
        Me.imlDriveTree.TransparentColor = System.Drawing.Color.Transparent
        Me.imlDriveTree.Images.SetKeyName(0, "Network_Drive.ico")
        Me.imlDriveTree.Images.SetKeyName(1, "HardDrive.ico")
        Me.imlDriveTree.Images.SetKeyName(2, "disc drive.ico")
        Me.imlDriveTree.Images.SetKeyName(3, "Removable.ico")
        Me.imlDriveTree.Images.SetKeyName(4, "Folder.ico")
        Me.imlDriveTree.Images.SetKeyName(5, "Open.ico")

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DirectoryViewer.jpg

Nasir Razzaq

It should work. Try to read through this example to see if you can spot any problem in your code

http://www.codeproject.com/KB/tree/UsingTreenodes.aspx

kingman1

ASKER

I still can't seem to get it to work, however I did find a work-around that works. It requires the user to add an imagelist control and assign it to the DirectoryViewer Control. They then have to call the following method in the form_load event.

DiretoryViewer1.SetImageList(ImageList2)

The code for the method is below.

Is there a way to run this method when the user assigns an imagelist to the ImageList property so they don't have to call the method? I tried doing an override of the imagelist property but it says it is protected.

Public Sub SetImageList(ByVal imlList As ImageList)

        imlList.TransparentColor = System.Drawing.Color.Transparent
        imlList.Images.Add(My.Resources.OSDrive_32)
        imlList.Images.Add(My.Resources.HardDrive_28)
        imlList.Images.Add(My.Resources.DiscDrive_26)
        imlList.Images.Add(My.Resources.Removable_40)
        imlList.Images.Add(My.Resources.NetworkDrive_29)
        imlList.Images.Add(My.Resources.ClosedFolder_034)
        imlList.Images.Add(My.Resources.OpenFolder_033)

    End Sub

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ASKER CERTIFIED SOLUTION

Nasir Razzaq

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kingman1

ASKER

I modified my code as suggested and it works. See below.

Thanks for the help. I appreciate it.

Public Sub SetImageList()

        Dim imlList As New ImageList

        imlList.TransparentColor = System.Drawing.Color.Transparent
        imlList.Images.Add(My.Resources.OSDrive2_32)
        imlList.Images.Add(My.Resources.HardDrive_28)
        imlList.Images.Add(My.Resources.DiscDrive_26)
        imlList.Images.Add(My.Resources.Removable_40)
        imlList.Images.Add(My.Resources.NetworkDrive_29)
        imlList.Images.Add(My.Resources.ClosedFolder2_034)
        imlList.Images.Add(My.Resources.OpenFolder2_033)

        MyBase.ImageList = imlList
        Me.ImageList = imlList

    End Sub

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Nasir Razzaq

Glad your problem is solved :-)