treeView-directory-browser.md

TreeView Directory Browser

To create an explorer-like file browser using TreeView:

• Create a tree view (named treeViewDir)
• Copy/paste this code block into your form
• Bind functions to events AfterSelect, BeforeExpand
• Call TreeViewDirInit() in your initialization routine

#region filesystem browser tree

private void TreeBrowserSelectPath(string path)
{
    path = System.IO.Path.GetFullPath(path);
    List<string> folderNames = new List<string>(path.Split(System.IO.Path.DirectorySeparatorChar));
    foreach (TreeNode driveNode in treeView1.Nodes)
    {
	if (folderNames.Count() == 0)
	    return;
	if (driveNode.Text + ":" == folderNames[0])
	    TreeBrowserExpandChildren(driveNode, folderNames);
    }
}

private void TreeBrowserExpandChildren(TreeNode node, List<string> children)
{
    children.RemoveAt(0);
    node.Expand();
    if (children.Count == 0)
	return;
    foreach (TreeNode mynode in node.Nodes)
	if (mynode.Text == children[0])
	{
	    treeView1.SelectedNode = mynode;
	    TreeBrowserExpandChildren(mynode, children);
	    break;
	}
}

private void TreeBrowserLoad()
{
    string[] drives = Environment.GetLogicalDrives();
    foreach (string drive in drives)
    {
	System.IO.DriveInfo di = new System.IO.DriveInfo(drive);
	int driveImage;

	// define icon based on drive type
	switch (di.DriveType)
	{
	    case System.IO.DriveType.CDRom:
		driveImage = 3;
		break;
	    case System.IO.DriveType.Network:
		driveImage = 6;
		break;
	    case System.IO.DriveType.NoRootDirectory:
		driveImage = 8;
		break;
	    case System.IO.DriveType.Unknown:
		driveImage = 8;
		break;
	    default:
		driveImage = 2;
		break;
	}

	TreeNode node = new TreeNode(drive.Substring(0, 1), driveImage, driveImage);
	node.Tag = drive;
	if (di.IsReady == true)
	    node.Nodes.Add("...");
	treeView1.Nodes.Add(node);
    }
}

private void treeView1_BeforeExpand(object sender, TreeViewCancelEventArgs e)
{
    if (e.Node.Nodes.Count > 0)
    {
	if (e.Node.Nodes[0].Text == "..." && e.Node.Nodes[0].Tag == null)
	{
	    e.Node.Nodes.Clear();

	    //get the list of sub direcotires
	    string[] dirs = System.IO.Directory.GetDirectories(e.Node.Tag.ToString());

	    foreach (string dir in dirs)
	    {
		System.IO.DirectoryInfo di = new System.IO.DirectoryInfo(dir);
		TreeNode node = new TreeNode(di.Name, 0, 1);

		try
		{
		    //keep the directory's full path in the tag for use later
		    node.Tag = dir;

		    //if the directory has sub directories add the place holder
		    if (di.GetDirectories().Count() > 0)
			node.Nodes.Add(null, "...", 0, 0);
		}
		catch (UnauthorizedAccessException)
		{
		    //display a locked folder icon
		    node.ImageIndex = 12;
		    node.SelectedImageIndex = 12;
		}
		catch (Exception ex)
		{
		    MessageBox.Show(ex.Message, "DirectoryLister",
			MessageBoxButtons.OK, MessageBoxIcon.Error);
		}
		finally
		{
		    e.Node.Nodes.Add(node);
		}
	    }
	}
    }
}

public event EventHandler PathSelected;
protected virtual void OnPathSelected(EventArgs e)
{
    var handler = PathSelected;
    if (handler != null)
	handler(this, e);
}

public string selectedPath = "C:";
private void treeView1_AfterSelect(object sender, TreeViewEventArgs e)
{
    string path = "";
    var mynode = e.Node;
    while (mynode != null)
    {
	path = mynode.Text + "/" + path;
	mynode = mynode.Parent;
    }
    path = path.Insert(1, ":");
    selectedPath = System.IO.Path.GetFullPath(path);
    Console.WriteLine($"PATH SELECTED: {selectedPath}");
    OnPathSelected(EventArgs.Empty);
}
#endregion

Adding Icons

Add an imagelist to your project and import the icons you want. Set smallImageList to your imagelist in the listView properties.

lvFolders.Items.Clear();
ListViewItem item = new ListViewItem();
item.ImageIndex = 1;
item.Text = "C:/";
item.ForeColor = Color.Blue;
lvFolders.Items.Add(item);

Adding Large (Image) Icons

public void SetFolder(string folder)
{
    // clear the old contents
    listView1.Items.Clear();

    // prepare the new image list
    ImageList imageList = new ImageList();
    int imageScale = 20;
    imageList.ImageSize = new Size(8 * imageScale, 6 * imageScale);
    listView1.LargeImageList = imageList;

    // load the image files
    foreach (string imagePath in ImageFilesInFolder(folder))
    {
	Image image = Image.FromFile(imagePath);
	imageList.Images.Add(image);

	ListViewItem item = new ListViewItem();
	item.Text = Path.GetFileNameWithoutExtension(imagePath);
	item.Text = item.Text.Replace("_", " ").Replace("-", " ");
	item.ImageIndex = imageList.Images.Count - 1;
	listView1.Items.Add(item);
    }

}