populate treeview from a list of path

Question

I'm trying to populate a treeview from a list of folder path, for example:

C:\WINDOWS\addins
C:\WINDOWS\AppPatch
C:\WINDOWS\AppPatch\MUI
C:\WINDOWS\AppPatch\MUI\040C
C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727
C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\MUI
C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\MUI\0409

with an ouput like this:

├───addins
├───AppPatch
│   └───MUI
│       └───040C
├───Microsoft.NET
│   └───Framework
│       └───v2.0.50727
│           └───MUI
│               └───0409

Notice there's no 'C:\\WINDOWS\\Microsoft.NET' or 'C:\\WINDOWS\\Microsoft.NET\\Framework' in the list. I've been working on this for almost two days and there's a bunch of bug in my code. Hope I can get help from here.

Thanks.

Eric

Answer 1

private void Form1_Load(object sender, EventArgs e)
    {
        var paths = new List<string>
                        {
                            @"C:\WINDOWS\AppPatch\MUI\040C",
                            @"C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727",
                            @"C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\MUI",
                            @"C:\WINDOWS\addins",
                            @"C:\WINDOWS\AppPatch",
                            @"C:\WINDOWS\AppPatch\MUI",
                            @"C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\MUI\0409"
                        };

        treeView1.PathSeparator = @"\";

        PopulateTreeView(treeView1, paths, '\\');
}


private static void PopulateTreeView(TreeView treeView, IEnumerable<string> paths, char pathSeparator)
    {
        TreeNode lastNode = null;
        string subPathAgg;
        foreach (string path in paths)
        {
            subPathAgg = string.Empty;
            foreach (string subPath in path.Split(pathSeparator))
            {
                subPathAgg += subPath + pathSeparator;
                TreeNode[] nodes = treeView.Nodes.Find(subPathAgg, true);
                if (nodes.Length == 0)
                    if (lastNode == null)
                        lastNode = treeView.Nodes.Add(subPathAgg, subPath);
                    else
                        lastNode = lastNode.Nodes.Add(subPathAgg, subPath);
                else
                    lastNode = nodes[0];
            }
        }
    }

Answer 2

for a linq'y version:

public static TreeNode MakeTreeFromPaths(List<string> paths, string rootNodeName = "", char separator = '/')
{
    var rootNode = new TreeNode(rootNodeName);
    foreach (var path in paths.Where(x => !string.IsNullOrEmpty(x.Trim()))) {
        var currentNode = rootNode;
        var pathItems = path.Split(separator);
        foreach (var item in pathItems) {
            var tmp = currentNode.Nodes.Cast<TreeNode>().Where(x => x.Text.Equals(item));
            currentNode = tmp.Count() > 0 ? tmp.Single() : currentNode.Nodes.Add(item);
        }
    }
    return rootNode;
}

Answer 3

ehosca answer correcr, but there is a little problem, when I change paths to like this

C:\WINDOWS\AppPatch\MUI\040C
D:\WIS\Microsoft.NET\Framework\v2.0.50727
E:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\MUI
C:\WINDOWS\addins
C:\WINDOWS\AppPatch
C:\WINDOWS\AppPatch\MUI
C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\MUI\0409

It will popoulate treeview like this.

But adding some extra code we can avoid this situation. So I changed the code in PopulateTreeView

private static void PopulateTreeView(TreeView treeView, string[] paths, char pathSeparator)
        {
            TreeNode lastNode = null;
            string subPathAgg;
            foreach (string path in paths)
            {
                subPathAgg = string.Empty;
                foreach (string subPath in path.Split(pathSeparator))
                {
                    subPathAgg += subPath + pathSeparator;
                    TreeNode[] nodes = treeView.Nodes.Find(subPathAgg, true);
                    if (nodes.Length == 0)
                        if (lastNode == null)
                            lastNode = treeView.Nodes.Add(subPathAgg, subPath);
                        else
                            lastNode = lastNode.Nodes.Add(subPathAgg, subPath);
                    else
                        lastNode = nodes[0];
                }
                lastNode = null; // This is the place code was changed

            }
        }

Now it works fine like this

Answer 4

I took your code, and it work very well, but i made just a little modification for improving the load speed when it is used whit a large list of files it seems like find operation, and string operations generally are very slow

private TreeNode PopulateTreeNode2(string[] paths, string pathSeparator)
    {
        if (paths == null)
            return null;

        TreeNode thisnode = new TreeNode();
        TreeNode currentnode;
        char[] cachedpathseparator = pathSeparator.ToCharArray();
        foreach (string path in paths)            {
            currentnode = thisnode;
            foreach (string subPath in path.Split(cachedpathseparator))
            {
                if (null == currentnode.Nodes[subPath])
                    currentnode = currentnode.Nodes.Add(subPath, subPath);
                else
                    currentnode = currentnode.Nodes[subPath];                   
            }
        }

        return thisnode;
    }

then you can use:

string[] paths =  {
                        @"C:\WINDOWS\AppPatch\MUI\040C",
                        @"D:\WINDOWS\Microsoft.NET\Framework\v2.0.50727",
                        @"E:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\MUI",
                        @"C:\WINDOWS\addins",
                        @"C:\WINDOWS\AppPatch",
                        @"C:\WINDOWS\AppPatch\MUI",
                        @"C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\MUI\0409"
                    };
TreeView treeview = new TreeView();
treeview.Nodes.Add(PopulateTreeNode2(paths, "\\"));

NOTE: maybe some string sensitivity check will be needed in both solutions, in order to prevent some folders re creations.

\n

because some url could be pointing to the same folder on the disk but spelled different such as: Windows ; WinDOWs , WINDOWS

Answer 5

Here's some very old code I once used to create an ASP.NET treeview from code (assuming TreeView has an ID of TreeViewFolders):

protected void Page_Load(object sender, EventArgs e)
{
    GenerateTreeView(@"C:\WINDOWS\");
}

private void GenerateTreeView(string rootPath)
{
    GetFolders(System.IO.Path.GetFullPath(rootPath), TreeViewFolders.Nodes);
    TreeViewFolders.ExpandDepth = 1;
}

// recursive method to load all folders and files into tree
private void GetFolders(string path, TreeNodeCollection nodes)
{
    // add nodes for all directories (folders)
    string[] dirs = Directory.GetDirectories(path);
    foreach (string p in dirs)
    {
        string dp = p.Substring(path.Length);
        nodes.Add(Node("", p.Substring(path.Length), "folder"));
    }

    // add nodes for all files in this directory (folder)
    string[] files = Directory.GetFiles(path, "*.*");
    foreach (string p in files)
    {
        nodes.Add(Node(p, p.Substring(path.Length), "file"));
    }

    // add all subdirectories for each directory (recursive)
    for (int i = 0; i < nodes.Count; i++)
    {
        if (nodes[i].Value == "folder")
            GetFolders(dirs[i] + "\\", nodes[i].ChildNodes);
    }
}

// create a TreeNode from the specified path, text and type
private TreeNode Node(string path, string text, string type)
{
    TreeNode n = new TreeNode();
    n.Value = type;
    n.Text = text;
    return n;
}

Answer 6

private void Form2_Load(object sender, EventArgs e)
{
    treeView1.CheckBoxes = true;

    foreach (TreeNode node in treeView1.Nodes)
    {
        node.Checked = true;
    }

    string[] drives = Environment.GetLogicalDrives();

    foreach (string drive in drives)
    {
        // treeView1.Nodes[0].Nodes[1].Checked = true;
        DriveInfo di = new DriveInfo(drive);
        int driveImage;

        switch (di.DriveType)   
        {
            case DriveType.CDRom:
                driveImage = 3;
                break;
            case DriveType.Network:
                driveImage = 6;
                break;
            case DriveType.NoRootDirectory:
                driveImage = 8;
                break;
            case 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);          
    }

    foreach (TreeNode node in treeView1.Nodes)
    {
        node.Checked = true;
    }
}

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();

                string[] dirs = Directory.GetDirectories(e.Node.Tag.ToString());

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

                    try
                    {
                        node.Tag = dir;
                        if (di.GetDirectories().Count() > 0)
                            node.Nodes.Add(null, "...", 0, 0).Checked = node.Checked;
                    }
                    catch (UnauthorizedAccessException)
                    {
                        node.ImageIndex = 12;
                        node.SelectedImageIndex = 12;
                    }
                    catch (Exception ex)
                    {
                        MessageBox.Show(ex.Message, "DirectoryLister", MessageBoxButtons.OK,
                        MessageBoxIcon.Error);
                    }
                    finally
                    {
                        node.Checked = e.Node.Checked;
                        e.Node.Nodes.Add(node);
                    }
                }
            }
        }
    }              
}

private void treeView1_AfterCheck(object sender, TreeViewEventArgs e)
{
    button1.Enabled = false;
    TreeNode node = e.Node;
    bool is_checked = node.Checked;
    foreach (TreeNode childNode in e.Node.Nodes)
    {
        childNode.Checked = e.Node.Checked;
    }
    treeView1.SelectedNode = node;
 }

Answer 7

I've managed to create a tree from path list using only for cycles. And it looks like it is the simpliest answer of this question at this moment.

Use this block of code to create a tree. list is the list of your files or folders, treeView1 is your TreeView.

//Creates a tree from given path list
foreach (string path in list)
{
    TreeNodeCollection nodes = treeView1.Nodes;

    foreach (string path_part in path.Split('\\'))
    {
        //Here it adds a new node (file or folder)
        if (!nodes.ContainsKey(path_part))
            nodes.Add(path_part, path_part);
        //Go one node deeper
        nodes = nodes[path_part].Nodes;
    }
}

Note - this may break if you use it with paths that start with the path separator (eg /home/user )

And if you want to remove common parts of your paths (or remove single parent nodes), use this block of code right after the previous one:

//This removes "single" TreeNodes (common paths)
while (treeView1.Nodes.Count == 1)
{
    //This "unpacks" child TreeNodes from the only parent TreeNode
    for (int i = 0; i < treeView1.Nodes[0].Nodes.Count; i++)
        treeView1.Nodes.Add(treeView1.Nodes[0].Nodes[i]);
    //This removes parent TreeNode
    treeView1.Nodes.RemoveAt(0);
}

This will generate an empty tree if all of your paths are the same.