How to Search and Drag-Drop Nodes in a TreeView Control

Posted by: Suprotim Agarwal , on 9/15/2008, in Category WinForms & WinRT
Views: 91350
Abstract: In this article, we will explore how to drag and drop nodes in a Treeview control. We will also explore how to search nodes in a TreeView.
How to Search and Drag-Drop Nodes in a TreeView Control
 
One of our dotnetcurry.com viewers Tim-Ann, asked me two queries about the TreeView control. He wanted to search a node and then move that node within the TreeView control. I thought of dedicating an article on it.
In this article, we will explore how to drag and drop nodes in a Treeview control. We will also explore how to search nodes in a TreeView.
Step 1: Create a Windows Forms Application. Drag and drop a Button(btnSearch) and a TextBox(txtSearch) on to the form.  Now add a TreeView(tvw) control to the form.
In the Form_Load() add the following code to populate the TreeView:
C#
private void Form1_Load(object sender, EventArgs e)
{
    treeView1.BeginUpdate();
    treeView1.Nodes.Add(".NET");
    treeView1.Nodes[0].Nodes.Add("Programming");
    treeView1.Nodes[0].Nodes[0].Nodes.Add("C#");
    treeView1.Nodes[0].Nodes[0].Nodes.Add("VB.NET");
    treeView1.Nodes.Add("Servers");
    treeView1.Nodes[1].Nodes.Add("Windows Server");
    treeView1.Nodes[1].Nodes[0].Nodes.Add("W2K3");
    treeView1.Nodes[1].Nodes[0].Nodes.Add("W2K8");
    treeView1.Nodes[1].Nodes.Add("SQL Server 2008");
    treeView1.Nodes[1].Nodes.Add("Exchange Server");
    // Expand all tree nodes when first loaded
    treeView1.ExpandAll();
    treeView1.EndUpdate();
    treeView1.AllowDrop = true;
}
VB.NET
Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs)
      treeView1.BeginUpdate()
      treeView1.Nodes.Add(".NET")
      treeView1.Nodes(0).Nodes.Add("Programming")
      treeView1.Nodes(0).Nodes(0).Nodes.Add("C#")
      treeView1.Nodes(0).Nodes(0).Nodes.Add("VB.NET")
      treeView1.Nodes.Add("Servers")
      treeView1.Nodes(1).Nodes.Add("Windows Server")
      treeView1.Nodes(1).Nodes(0).Nodes.Add("W2K3")
      treeView1.Nodes(1).Nodes(0).Nodes.Add("W2K8")
      treeView1.Nodes(1).Nodes.Add("SQL Server 2008")
      treeView1.Nodes(1).Nodes.Add("Exchange Server")
      ' Expand all tree nodes when first loaded
      treeView1.ExpandAll()
      treeView1.EndUpdate()
      treeView1.AllowDrop = True
End Sub
Step 2: We will first create the functionality to ‘Search’ a TreeView. On the btnSearch click event, add the following code:
C#
private void FindInTreeView(TreeNodeCollection tncoll, string strNode)
{
    foreach (TreeNode tnode in tncoll)
    {
        if (tnode.Text.ToLower() == strNode.ToLower())
        {
            tnode.ForeColor = Color.Blue;
            tnode.TreeView.SelectedNode = tnode;
        }
        else
        {
            tnode.BackColor = tnode.TreeView.BackColor;
        }
        FindInTreeView(tnode.Nodes, strNode);
    }
}
 
VB.NET
Private Sub FindInTreeView(ByVal tncoll As TreeNodeCollection, ByVal strNode As String)
      For Each tnode As TreeNode In tncoll
            If tnode.Text.ToLower() = strNode.ToLower() Then
                  tnode.ForeColor = Color.Blue
                  tnode.TreeView.SelectedNode = tnode
            Else
                  tnode.BackColor = tnode.TreeView.BackColor
            End If
            FindInTreeView(tnode.Nodes, strNode)
      Next tnode
End Sub
 
The code above searches the nodes recursively. Using a ForEach loop, we traverse the nodes and then compare the search item with the treenode text. If it matches, we highlight the node with a different color.
Step 3: Let us now add functionality to drag and drop nodes in the TreeView. We would first need to register a few events as shown below:
C#
private void RegisterEvents()
{
    this.tvw.DragDrop += new System.Windows.Forms.DragEventHandler(this.tvw_DragDrop);
    this.tvw.DragEnter += new System.Windows.Forms.DragEventHandler(this.tvw_DragEnter);
    this.tvw.ItemDrag += new System.Windows.Forms.ItemDragEventHandler(this.tvw_ItemDrag);
}
VB.NET
Private Sub RegisterEvents()
      AddHandler tvw.DragDrop, AddressOf tvw_DragDrop
      AddHandler tvw.DragEnter, AddressOf tvw_DragEnter
      AddHandler tvw.ItemDrag, AddressOf tvw_ItemDrag
End Sub
Note: Call the RegisterEvents() in your Form_Load.
The next step is to add functionality to these event handlers :
C#
private void tvw_ItemDrag(object sender, ItemDragEventArgs e)
{
    tvw.DoDragDrop(e.Item, DragDropEffects.Move);
}
 
private void tvw_DragEnter(object sender, DragEventArgs e)
{
    e.Effect = DragDropEffects.Move;
}
 
private void tvw_DragDrop(object sender, DragEventArgs e)
{
    Point loc = ((TreeView)sender).PointToClient(new Point(e.X, e.Y));
    TreeNode node = (TreeNode)e.Data.GetData(typeof(TreeNode));
    TreeNode destNode = ((TreeView)sender).GetNodeAt(loc);
 
    if (node.Parent == null)
        node.TreeView.Nodes.Remove(node);
    else
        node.Parent.Nodes.Remove(node);
 
    if (destNode.Parent == null)
        destNode.TreeView.Nodes.Insert(destNode.Index + 1, node);
    else
        destNode.Parent.Nodes.Insert(destNode.Index + 1, node);
}
VB.NET
Private Sub tvw_ItemDrag(ByVal sender As Object, ByVal e As ItemDragEventArgs)
      tvw.DoDragDrop(e.Item, DragDropEffects.Move)
End Sub
 
Private Sub tvw_DragEnter(ByVal sender As Object, ByVal e As DragEventArgs)
      e.Effect = DragDropEffects.Move
End Sub
 
Private Sub tvw_DragDrop(ByVal sender As Object, ByVal e As DragEventArgs)
      Dim loc As Point = (CType(sender, TreeView)).PointToClient(New Point(e.X, e.Y))
      Dim node As TreeNode = CType(e.Data.GetData(GetType(TreeNode)), TreeNode)
      Dim destNode As TreeNode = (CType(sender, TreeView)).GetNodeAt(loc)
 
      If node.Parent Is Nothing Then
            node.TreeView.Nodes.Remove(node)
      Else
            node.Parent.Nodes.Remove(node)
      End If
 
      If destNode.Parent Is Nothing Then
            destNode.TreeView.Nodes.Insert(destNode.Index + 1, node)
      Else
            destNode.Parent.Nodes.Insert(destNode.Index + 1, node)
      End If
End Sub
As shown in the code above, the ItemDrag event is raised from the TreeView control as soon as the user starts to drag the tree node. The DoDragDrop method initiates the drag-and-drop procedure.
The DragEnter event occurs when the TreeNode object is dragged from one point of the TreeView control to another point within the TreeView control. In this event, you can check the validity of the drag operation.
Finally the DragDrop event occurs when the TreeNode object is dropped at the destination point of the TreeView control. The drop point is calculated and the TreeNode object is retrieved, that is to be added to the destination node. That is all the code that is needed to initiate a drag and drop. Just make sure that the ‘AllowDrop’ property on the TreeView is set to True.
In this article, we explored how to search nodes in a TreeView control. We also explored how to drag and drop nodes in a treeview control. I hope this article was useful and I thank you for viewing it. 
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Author
Suprotim Agarwal, MCSD, MCAD, MCDBA, MCSE, is the founder of DotNetCurry, DNC Magazine for Developers, SQLServerCurry and DevCurry. He has also authored a couple of books 51 Recipes using jQuery with ASP.NET Controls and a new one recently at The Absolutely Awesome jQuery CookBook.

Suprotim has received the prestigious Microsoft MVP award for nine times in a row now. In a professional capacity, he is the CEO of A2Z Knowledge Visuals Pvt Ltd, a digital group that represents premium web sites and digital publications comprising of Professional web, windows, mobile and cloud developers, technical managers, and architects.

Get in touch with him on Twitter @suprotimagarwal, LinkedIn or befriend him on Facebook



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Feedback - Leave us some adulation, criticism and everything in between!
Comment posted by sasi on Monday, October 6, 2008 6:18 AM
some what needed
Comment posted by Gabor Kovacs on Wednesday, February 11, 2009 9:51 AM
Bug in this code, if you select tree node and move to selves then selected node is deleted.

Fix in c# code:

  TreeNode destNode = ((TreeView)sender).GetNodeAt(loc);

+ if (node == destNode) return;

  if (node.Parent == null)
Comment posted by chaman gonzalves on Friday, March 20, 2009 5:51 PM
private TreeNode findNodeInTree(TreeNodeCollection coll, string nodeText)
        {
            int nodeCount = 0;
            TreeNode retNode = null;
            foreach (TreeNode nd in coll)
            {
                if (nd.Text == nodeText)
                {
                    retNode = nd;
                    break;
                }
                else
                {
                    nodeCount++;
                }
                if(nodeCount == coll.Count)
                    findNodeInTree(nd.Nodes, nodeText);
            }            
            return retNode;
Comment posted by chaman gonzalves on Monday, March 23, 2009 9:20 AM
private TreeNode findNodeInTree(TreeNodeCollection coll, string nodeText)
        {
            int nodeCount = 0;
            TreeNode retNode = null;
            foreach (TreeNode nd in coll)
            {
                if (nd.Text == nodeText)
                {
                    retNode = nd;
                    break;
                }
                else
                {
                    nodeCount++;
                }
                if(nodeCount == coll.Count)
                    findNodeInTree(nd.Nodes, nodeText);
            }            
            return retNode;
Comment posted by mahi@swetha1 on Thursday, July 2, 2009 8:44 AM
My friends,
how to implement expandable and collapsible properties for usercontrol?
I request u to help me in sorting out a solution for a usercontrol made up of two panels.I like to implement expandable and collapsable features to usercontrol.So that the child controls or usercontrols placed below it should shift upwards and downwards.
In the same usercontrol,How can i proceed if i like to resize the usercontrol at design time as well as runtime?


using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Text;
using System.Windows.Forms;
  
namespace Freshm
{
[Designer(typeof(Freshm1))]
public partial class UserControl1 : UserControl
{
public UserControl1()
{
InitializeComponent();
}
private void UserControl1_Load(object sender, EventArgs e)
{
button1.Visible = false;
button2.Visible = true;
panel2.Visible = true;
//if (button2.Visible == true)
//{
// this.Height = 52;
// this.Width = 150;
//}
}
#region button_click events
private void button2_Click(object sender, EventArgs e)
{
button2.Visible = false;
button1.Visible = true;
panel2.Visible = false;
if (button2.Visible == false)
{
this.Height = 52;
this.Width = 150;
panel1.Height = this.Height;
panel1.Width = this.Width;
}
}
private void button1_Click(object sender, EventArgs e)
{
button1.Visible = false;
button2.Visible = true;
panel2.Visible = true;
if (button2.Visible == true)
{
this.Height = 146;
this.Width = 150;
panel1.Height = this.Height;
panel1.Width = this.Width;
}
}
#endregion

#region Serialization
[DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
public Panel ControlPanel
{
get
{
return this.panel1;
}

}
[DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
public Panel ControlPanel2
{
get
{
return this.panel2;
}
}
#endregion
#region Properties
public string DisplayText
{
get
{
return this.label1.Text;
}
set
{
label1.Text = value;
}
}
public System.Drawing.Font TextFont
{
get
{
return this.label1.Font;
}
set
{
label1.Font = value;
}
}
public System.Drawing.Color pnl1TextColor
{
get
{
return this.panel1.BackColor;
}
set
{
panel1.BackColor = value;
}
}
public Color pnl2TextColor
{
get
{
return this.panel2.BackColor;
}
set
{
panel2.BackColor = value;
}
}
public Color UCTextColor
{
get
{
return this.BackColor;
}
set
{
this.BackColor = value;
}
}
public Size UCTextsize
{
get
{
return this.Size;
}
set
{
this.Size = value;
}
}
#endregion
//private void button1_Click(Object sender,System.EventArgs e)
//{

//}
//#region Fields
//private ToggleButton btnExpandOrCollapse;
//private FrameworkElement contentElement;
//private VisualState collapsedState;
//#endregion
//public bool IsExpanded
//{
// get { return (bool)GetValue(IsExpandedProperty); }
// set
// {
// SetValue(IsExpandedProperty, value);
// if (btnExpandOrCollapse != null)
// btnExpandOrCollapse.IsChecked = IsExpanded;
// }
//}
  
}
}
  
  
  
  
  
  
  
using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms.Design;
namespace Freshm
{
public class Freshm1 : ParentControlDesigner
{
public override void Initialize(System.ComponentModel.IComponent component)
{
base.Initialize(component);
if (this.Control is UserControl1)
{
this.EnableDesignMode(((UserControl1)this.Control).ControlPanel, "ControlPanel");
this.EnableDesignMode(((UserControl1)this.Control).ControlPanel2, "ControlPanel2");
}
}
}
}
  
  
  
  
  
namespace Freshm
{
partial class UserControl1
{
/// <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 Component 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.panel1 = new System.Windows.Forms.Panel();
this.label1 = new System.Windows.Forms.Label();
this.button2 = new System.Windows.Forms.Button();
this.button1 = new System.Windows.Forms.Button();
this.panel2 = new System.Windows.Forms.Panel();
this.panel1.SuspendLayout();
this.SuspendLayout();
//
// panel1
//
this.panel1.BackColor = System.Drawing.SystemColors.AppWorkspace;
this.panel1.Controls.Add(this.label1);
this.panel1.Controls.Add(this.button2);
this.panel1.Controls.Add(this.button1);
this.panel1.Location = new System.Drawing.Point(0, 3);
this.panel1.Name = "panel1";
this.panel1.Size = new System.Drawing.Size(150, 52);
this.panel1.TabIndex = 0;
//
// label1
//
this.label1.BackColor = System.Drawing.SystemColors.ActiveCaptionText;
this.label1.Font = new System.Drawing.Font("Times New Roman", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
this.label1.ForeColor = System.Drawing.SystemColors.ControlText;
this.label1.Location = new System.Drawing.Point(31, 10);
this.label1.Margin = new System.Windows.Forms.Padding(3);
this.label1.Name = "label1";
this.label1.Size = new System.Drawing.Size(96, 14);
this.label1.TabIndex = 2;
this.label1.Text = "Enter Ur Name";
//
// button2
//
this.button2.Image = global::Freshm.Properties.Resources.NORMALGROUPCOLLAPSE;
this.button2.Location = new System.Drawing.Point(3, 3);
this.button2.Name = "button2";
this.button2.Size = new System.Drawing.Size(22, 23);
this.button2.TabIndex = 1;
this.button2.UseVisualStyleBackColor = true;
this.button2.Click += new System.EventHandler(this.button2_Click);
//
// button1
//
this.button1.Image = global::Freshm.Properties.Resources.NORMALGROUPEXPAND;
this.button1.Location = new System.Drawing.Point(3, 3);
this.button1.Name = "button1";
this.button1.Size = new System.Drawing.Size(22, 23);
this.button1.TabIndex = 0;
this.button1.UseVisualStyleBackColor = true;
this.button1.Click += new System.EventHandler(this.button1_Click);
//
// panel2
//
this.panel2.BackColor = System.Drawing.SystemColors.ButtonShadow;
this.panel2.Location = new System.Drawing.Point(0, 53);
this.panel2.Name = "panel2";
this.panel2.Size = new System.Drawing.Size(150, 94);
this.panel2.TabIndex = 1;
//
// UserControl1
//
this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
this.Controls.Add(this.panel2);
this.Controls.Add(this.panel1);
this.Location = new System.Drawing.Point(0, -2);
this.Name = "UserControl1";
this.Size = new System.Drawing.Size(150, 145);
this.Load += new System.EventHandler(this.UserControl1_Load);
this.panel1.ResumeLayout(false);
this.ResumeLayout(false);
}
#endregion
private System.Windows.Forms.Panel panel1;
private System.Windows.Forms.Label label1;
private System.Windows.Forms.Button button2;
private System.Windows.Forms.Button button1;
private System.Windows.Forms.Panel panel2;
}
}



      
Comment posted by Henrik on Wednesday, January 14, 2015 3:41 PM
Thanks for sharing but you should add a few more lines to avoid crashes ;)

Private Sub tvw_DragDrop(ByVal sender As Object, ByVal e As DragEventArgs) Handles TreeView1.DragDrop
        Dim loc As Point = (CType(sender, TreeView)).PointToClient(New Point(e.X, e.Y))
        Dim node As TreeNode = CType(e.Data.GetData(GetType(TreeNode)), TreeNode)
        Dim destNode As TreeNode = (CType(sender, TreeView)).GetNodeAt(loc)

        If Not node Is destNode And Not destNode Is Nothing Then
            If node.Parent Is Nothing Then
                node.TreeView.Nodes.Remove(node)
            Else
                node.Parent.Nodes.Remove(node)
            End If

            If destNode.Parent Is Nothing Then
                destNode.TreeView.Nodes.Insert(destNode.Index + 1, node)
            Else
                destNode.Parent.Nodes.Insert(destNode.Index + 1, node)
            End If
        End If
    End Sub
Comment posted by Suprotim Agarwal on Monday, January 19, 2015 9:05 PM
@Henrik: This article was written about 7 yrs ago and I have lost track of it since then. Thanks for sharing your code.

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