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C# drag and drop treeview item

In C# I'm trying to implement drag and drop functionality
I used code:

private void treeView1_MouseDown(object sender, MouseEventArgs e)
        {
            treeView1.Select();
        }

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private void treeView1_ItemDrag(object sender, ItemDragEventArgs e)
        {
             if (treeView1.SelectedNode.FullPath.Substring(treeView1.SelectedNode.FullPath.Length - 4, 4).ToLower() == ".pdf")
            {

                ls_selected_node = treeView1.SelectedNode.FullPath;
            }
            if(string.IsNullOrEmpty(ls_selected_node) == true)
            {
                MessageBox.Show("Select a valid File.", "Warning",MessageBoxButtons.OK,MessageBoxIcon.Warning);
                return;
            }

            if (e.Button == MouseButtons.Left)
            {

                string file = dirpath1_t + ls_policy_no + "\\" + ls_selected_node;
                string[] files = new string[1];
                files[0] = @file;
                DataObject data = new DataObject(DataFormats.FileDrop, files);
                DoDragDrop(data, DragDropEffects.Copy);
                ls_selected_node = "";
            }
        }

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But when I press mouse button on a third level node, I got a root node value and if I use event:

private void treeView1_AfterSelect(object sender, TreeViewEventArgs e)
        {
           treeView1.Select();
        }

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user has to click twice, first to select and second to drag, how to do it in a right way?

it_saige

Here is an example of how to do it:

Form1.cs -

using System;
using System.Drawing;
using System.IO;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace EE_Q29135568
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            PopulateTreeView1();
            PopulateTreeView2();
        }

        private string GetImageKey(string fullName, string extension)
        {
            Icon iconForFile = SystemIcons.WinLogo;
            IntPtr hImgSmall;
            SHFILEINFO shinfo = new SHFILEINFO();
            if (string.IsNullOrEmpty(extension))
                extension = "folder";

            if (!imageList1.Images.ContainsKey(extension))
            {
                hImgSmall = NativeMethods.SHGetFileInfo(fullName, 0, ref shinfo, (uint)Marshal.SizeOf(shinfo), NativeMethods.SHGFI_ICON | NativeMethods.SHGFI_SMALLICON);
                iconForFile = Icon.FromHandle(shinfo.hIcon);
                imageList1.Images.Add(extension, iconForFile);
            }
            return extension;
        }

        private void PopulateTreeView1()
        {
            TreeNode rootNode;

            DirectoryInfo info = new DirectoryInfo(@"../..");
            if (info.Exists)
            {
                rootNode = new TreeNode(info.Name);
                rootNode.Tag = info;
                GetDirectories(info.GetDirectories(), rootNode);
                treeView1.Nodes.Add(rootNode);
            }
        }

        private void PopulateTreeView2()
        {
            TreeNode rootNode;

            DirectoryInfo info = new DirectoryInfo(@"../..");
            if (info.Exists)
            {
                rootNode = new TreeNode(info.Name);
                rootNode.Tag = info;
                GetDirectories(info.GetDirectories(), rootNode);
                treeView2.Nodes.Add(rootNode);
            }
        }

        private void GetDirectories(DirectoryInfo[] parent, TreeNode nodeToAddTo)
        {
            TreeNode aNode;
            DirectoryInfo[] children;
            foreach (DirectoryInfo child in parent)
            {
                aNode = new TreeNode(child.Name, 0, 0);
                aNode.Tag = child;
                aNode.ImageKey = GetImageKey(child.FullName, child.Extension);
                children = child.GetDirectories();
                if (children.Length != 0)
                    GetDirectories(children, aNode);
                nodeToAddTo.Nodes.Add(aNode);
            }
        }

        private void OnDragEnter(object sender, DragEventArgs e)
        {
            e.Effect = DragDropEffects.Move;
        }

        private void OnDragDrop(object sender, DragEventArgs e)
        {
            if (e.Data.GetDataPresent(typeof(TreeNode).FullName, true))
            {
                var tree = sender as TreeView;
                Point point = tree.PointToClient(new Point(e.X, e.Y));
                TreeNode destination = tree.GetNodeAt(point);
                TreeNode data = e.Data.GetData(typeof(TreeNode)) as TreeNode;

                if (!ReferenceEquals(destination, data))
                {
                    destination.Nodes.Add(data.Clone() as TreeNode);
                    destination.Expand();
                    data.Remove();
                }
            }
        }

        private void OnItemDrag(object sender, ItemDragEventArgs e)
        {
            DoDragDrop(e.Item, DragDropEffects.Move);
        }
    }

    [StructLayout(LayoutKind.Sequential)]
    public struct SHFILEINFO
    {
        public IntPtr hIcon;
        public int iIcon;
        public uint dwAttributes;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]
        public string szDisplayName;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 80)]
        public string szTypeName;
    };

    class NativeMethods
    {
        public const uint SHGFI_ICON = 0x100;
        public const uint SHGFI_LARGEICON = 0x0; // 'Large icon
        public const uint SHGFI_SMALLICON = 0x1; // 'Small icon

        [DllImport("shell32.dll")]
        public static extern IntPtr SHGetFileInfo(string pszPath, uint dwFileAttributes, ref SHFILEINFO psfi, uint cbSizeFileInfo, uint uFlags);
    }
}

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Form1.Designer.cs -

namespace EE_Q29135568
{
    partial class Form1
    {
        /// <summary>
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows Form Designer generated code

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.components = new System.ComponentModel.Container();
            this.splitContainer1 = new System.Windows.Forms.SplitContainer();
            this.treeView1 = new System.Windows.Forms.TreeView();
            this.treeView2 = new System.Windows.Forms.TreeView();
            this.imageList1 = new System.Windows.Forms.ImageList(this.components);
            ((System.ComponentModel.ISupportInitialize)(this.splitContainer1)).BeginInit();
            this.splitContainer1.Panel1.SuspendLayout();
            this.splitContainer1.Panel2.SuspendLayout();
            this.splitContainer1.SuspendLayout();
            this.SuspendLayout();
            // 
            // splitContainer1
            // 
            this.splitContainer1.Dock = System.Windows.Forms.DockStyle.Fill;
            this.splitContainer1.Location = new System.Drawing.Point(0, 0);
            this.splitContainer1.Name = "splitContainer1";
            // 
            // splitContainer1.Panel1
            // 
            this.splitContainer1.Panel1.Controls.Add(this.treeView1);
            // 
            // splitContainer1.Panel2
            // 
            this.splitContainer1.Panel2.Controls.Add(this.treeView2);
            this.splitContainer1.Size = new System.Drawing.Size(800, 450);
            this.splitContainer1.SplitterDistance = 382;
            this.splitContainer1.TabIndex = 0;
            // 
            // treeView1
            // 
            this.treeView1.AllowDrop = true;
            this.treeView1.Dock = System.Windows.Forms.DockStyle.Fill;
            this.treeView1.Location = new System.Drawing.Point(0, 0);
            this.treeView1.Name = "treeView1";
            this.treeView1.Size = new System.Drawing.Size(382, 450);
            this.treeView1.TabIndex = 0;
            this.treeView1.ItemDrag += new System.Windows.Forms.ItemDragEventHandler(this.OnItemDrag);
            this.treeView1.DragDrop += new System.Windows.Forms.DragEventHandler(this.OnDragDrop);
            this.treeView1.DragEnter += new System.Windows.Forms.DragEventHandler(this.OnDragEnter);
            // 
            // treeView2
            // 
            this.treeView2.AllowDrop = true;
            this.treeView2.Dock = System.Windows.Forms.DockStyle.Fill;
            this.treeView2.Location = new System.Drawing.Point(0, 0);
            this.treeView2.Name = "treeView2";
            this.treeView2.Size = new System.Drawing.Size(414, 450);
            this.treeView2.TabIndex = 0;
            this.treeView2.ItemDrag += new System.Windows.Forms.ItemDragEventHandler(this.OnItemDrag);
            this.treeView2.DragDrop += new System.Windows.Forms.DragEventHandler(this.OnDragDrop);
            this.treeView2.DragEnter += new System.Windows.Forms.DragEventHandler(this.OnDragEnter);
            // 
            // imageList1
            // 
            this.imageList1.ColorDepth = System.Windows.Forms.ColorDepth.Depth8Bit;
            this.imageList1.ImageSize = new System.Drawing.Size(16, 16);
            this.imageList1.TransparentColor = System.Drawing.Color.Transparent;
            // 
            // Form1
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(800, 450);
            this.Controls.Add(this.splitContainer1);
            this.Name = "Form1";
            this.Text = "Form1";
            this.splitContainer1.Panel1.ResumeLayout(false);
            this.splitContainer1.Panel2.ResumeLayout(false);
            ((System.ComponentModel.ISupportInitialize)(this.splitContainer1)).EndInit();
            this.splitContainer1.ResumeLayout(false);
            this.ResumeLayout(false);

        }

        #endregion

        private System.Windows.Forms.SplitContainer splitContainer1;
        private System.Windows.Forms.TreeView treeView1;
        private System.Windows.Forms.TreeView treeView2;
        private System.Windows.Forms.ImageList imageList1;
    }
}

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Which produces the following output -

-saige-

ybt

ASKER

You probably did not realize what I need I have a treeview and need to drag pdf item and drop it to outlook email treeview image attached
treeview.JPG

it_saige

The example solution shows how you can drag node's from one location to another in the same tree and even across tree views.

-saige-

ybt

ASKER

In my case this part of code:
aNode.ImageKey = GetImageKey(child.FullName, child.Extension);
children = child.GetDirectories();
is not working
children.Length always 0

it_saige

Most likely there are not any child directories or you do not have access to them. You can change the path that the methods look in; in the PopulateTreeView methods, just change the line:

DirectoryInfo info = new DirectoryInfo(@"put whatever path you want here");

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-saige-

ASKER CERTIFIED SOLUTION

ybt

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