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ComboBoxTree

, 2 Feb 2004
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A treeview control that drops down much like a combobox.

Sample Image

Introduction

The ComboBoxTree control expands on Gevik Babakhani's DropDown Treeview control. Nearly 85% of the code has been rewritten. This updated control provides the following enhancements:

  • Treeview can be sized beyond the width of its parents and the form.
  • The sizing grip functionality is more consistent with standard Windows sizing grips.
  • Node selection populates the box when it is a root node, the SelectionSeparator property assigns the separator (i.e. a SelectionSeperator that is a period '.' would generate something like: Node0.subnode1.subnode2.rootnode).
  • Better design-time support including the standard treeview WYSIWYG editor.
  • The selected node box is editable and accessible as a property - however there is no validation on this value when set manually.
  • Simplified, by using regions and less method calls.

Please feel free to post comments, questions or criticism. This is my first Windows control, so feedback is appreciated.

Background

I needed a control for a project that required multiple treeviews but had very limited form space. When I found Gevik's DropDown TreeView, I was relieved to find what I was looking for but soon ran into problems that required attention and hours of code updating.

Originally, I didn't intend to redistribute the updated control, but I wanted to give back as a way of saying thanks. Thanks goes out to The Code Project and the original author - thanks Gevik Babakhani Wink | ;-)

To use the control, simply add the ComboBoxTree.dll file to your toolbox and drop the control onto your form. The control should provide most of the treeview functionality you require.

Points of Interest

I was able to get around the "sizing beyond parent" problem by adding the treeview to its own borderless form. My next problem involved making the sizing grip work correctly. I was able to get this going by calculating the offset of the mouse within the sizing grip along with the absolute mouse position and the location of the form containing the treeview. My final big problem was the sizing grip when scroll bars showed. Disabling scroll bars wasn't a solution so my only alternative was to add a margin of space on the bottom and right-hand side. A bit different but definitely functional!

History

  • 01/26/04 Version 1.0 submitted.
  • 02/02/04 Version 1.2 submitted, changes include:
    • Text property is now overridden.
    • AbsoluteChildrenSelectableOnly property option now available, users can now select end nodes only or all nodes.
    • Public ValidateText method now available to validate manually entered text.
    • SelectionSeparator now called BranchSeparater.
    • Minor toolbox category changes.

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here

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About the Author

Gabe Anguiano

United States United States
No Biography provided

Comments and Discussions

 
QuestionNo NodeSelectEventHandler event? Pinmemberlocketine17-Dec-12 15:07 
QuestionCan't change size PinmemberMVictorL18-Nov-12 23:09 
QuestionHandling the Enter key PinmemberMember 390355925-Oct-12 11:55 
QuestionHow to show image of the selected tree item in combobox PinmemberRui Frazao9-Jun-10 7:07 
GeneralCheckbox With Every Node PinmemberFarid_Bilal26-Feb-09 21:58 
QuestionHow to populate tree with data from datatable ? Pinmemberloverboy2312-Jul-08 4:49 
QuestionHow can i get DropDownStyle like combobox? PinmemberMember 137660010-Apr-08 4:07 
GeneralBranchSeparator as String, DropDownHeight, ... Pinmemberfraveu27-Sep-07 10:53 
GeneralRe: BranchSeparator as String, DropDownHeight, ... Pinmemberfraveu27-Sep-07 10:55 
using System;
using System.ComponentModel;
using System.Drawing;
using System.Resources;
using System.Text.RegularExpressions;
using System.Windows.Forms;
 
namespace Verlinea.ComboBoxTree {
public delegate void NodeSelectEventHandler();
///
/// ComboBoxTree control is a treeview that drops down much like a combobox
///

public class ComboBoxTree : UserControl {
#region Private Fields
private Panel pnlBack;
private Panel pnlTree;
private TextBox tbSelectedValue;
private ButtonEx btnSelect;
private TreeView tvTreeView;
private LabelEx lblSizingGrip;
private Form frmTreeView;
 
private string _branchSeparator;
private bool _absoluteChildrenSelectableOnly;
private int _dropDownHeight;
private System.Drawing.Point DragOffset;
#endregion
#region Public Properties
[Browsable(true), Description("Gets the TreeView Nodes collection"), Category("TreeView"), DesignerSerializationVisibility(DesignerSerializationVisibility.Content), Editor(typeof(TreeNodeCollection), typeof(TreeNodeCollection))]
public TreeNodeCollection Nodes {
get {
return this.tvTreeView.Nodes;
}
}
 
[Browsable(true), Description("Gets or sets the TreeView's Selected Node"), Category("TreeView")]
public TreeNode SelectedNode {
set {
this.tvTreeView.SelectedNode = value;
}
}
 
[Browsable(true), Description("Gets or sets the TreeView's Selected Node"), Category("TreeView")]
public ImageList Imagelist {
get { return this.tvTreeView.ImageList; }
set { this.tvTreeView.ImageList = value; }
}
 
[Browsable(true), Description("The text in the ComboBoxTree control"), Category("Appearance")]
public override string Text {
get { return this.tbSelectedValue.Text; }
set { this.tbSelectedValue.Text = value; }
}
 
[Browsable(true), Description("Gets or sets the separator for the selected node's value"), Category("Appearance")]
public string BranchSeparator {
get { return this._branchSeparator; }
set {
if (value.Length > 0)
this._branchSeparator = value/*.Substring(0,1)*/;
}
}
 
[Browsable(true), Description("Gets or sets the separator for the selected node's value"), Category("Behavior")]
public bool AbsoluteChildrenSelectableOnly {
get { return this._absoluteChildrenSelectableOnly; }
set { this._absoluteChildrenSelectableOnly = value; }
}
 
[Browsable(true), Description("The heigth, in pixels, of the treeview in a combobox."), Category("Behavior")]
public int DropDownHeight {
get { return this._dropDownHeight; }
set { this._dropDownHeight = value; }
}
#endregion
 
public ComboBoxTree() {
this.InitializeComponent();
 
// Initializing Controls
this.pnlBack = new Panel();
this.pnlBack.BorderStyle = BorderStyle.Fixed3D;
this.pnlBack.BackColor = Color.White;
this.pnlBack.AutoScroll = false;
 
this.tbSelectedValue = new TextBox();
this.tbSelectedValue.BorderStyle = System.Windows.Forms.BorderStyle.None;
 
this.btnSelect = new ButtonEx();
this.btnSelect.Click += new EventHandler(ToggleTreeView);
this.btnSelect.FlatStyle = FlatStyle.Flat;
 
this.lblSizingGrip = new LabelEx();
this.lblSizingGrip.Size = new Size(9, 9);
this.lblSizingGrip.BackColor = Color.Transparent;
this.lblSizingGrip.Cursor = Cursors.SizeNWSE;
this.lblSizingGrip.MouseMove += new MouseEventHandler(SizingGripMouseMove);
this.lblSizingGrip.MouseDown += new MouseEventHandler(SizingGripMouseDown);
 
this.tvTreeView = new TreeView();
this.tvTreeView.BorderStyle = BorderStyle.None;
this.tvTreeView.DoubleClick += new EventHandler(TreeViewNodeSelect);
this.tvTreeView.Location = new Point(0, 0);
this.tvTreeView.LostFocus += new EventHandler(TreeViewLostFocus);
//this.tvTreeView.Scrollable = false;
 
this.frmTreeView = new Form();
this.frmTreeView.FormBorderStyle = FormBorderStyle.None;
this.frmTreeView.StartPosition = FormStartPosition.Manual;
this.frmTreeView.ShowInTaskbar = false;
this.frmTreeView.BackColor = System.Drawing.SystemColors.Control;
 
this.pnlTree = new Panel();
this.pnlTree.BorderStyle = BorderStyle.FixedSingle;
this.pnlTree.BackColor = Color.White;
 
SetStyle(ControlStyles.DoubleBuffer, true);
SetStyle(ControlStyles.ResizeRedraw, true);
 
// Adding Controls to UserControl
this.pnlTree.Controls.Add(this.lblSizingGrip);
this.pnlTree.Controls.Add(this.tvTreeView);
this.frmTreeView.Controls.Add(this.pnlTree);
this.pnlBack.Controls.AddRange(new Control[] { btnSelect, tbSelectedValue });
this.Controls.Add(this.pnlBack);
}
 
private void RelocateGrip() {
this.lblSizingGrip.Top = this.frmTreeView.Height - lblSizingGrip.Height - 1;
this.lblSizingGrip.Left = this.frmTreeView.Width - lblSizingGrip.Width - 1;
}
 
private void ToggleTreeView(object sender, EventArgs e) {
if (!this.frmTreeView.Visible) {
Rectangle CBRect = this.RectangleToScreen(this.ClientRectangle);
this.frmTreeView.Location = new System.Drawing.Point(CBRect.X, CBRect.Y + this.pnlBack.Height);
 
this.frmTreeView.Show();
this.frmTreeView.BringToFront();
 
this.RelocateGrip();
//this.tbSelectedValue.Text = "";
} else {
this.frmTreeView.Hide();
}
}
 
public bool ValidateText() {
const char splitChar = '&';
string ValidatorText = this.Text.Replace(this._branchSeparator, splitChar.ToString());
TreeNodeCollection TNC = this.tvTreeView.Nodes;
 
for (int i = 0; i < ValidatorText.Split(splitChar/*this._branchSeparator.ToCharArray()[0]*/).Length; i++) {
bool NodeFound = false;
string NodeToFind = ValidatorText.Split(splitChar/*this._branchSeparator.ToCharArray()[0]*/)[i];
for (int j = 0; j < TNC.Count; j++) {
if (TNC[j].Text == NodeToFind) {
NodeFound = true;
TNC = TNC[j].Nodes;
break;
}
}
 
if (!NodeFound)
return false;
}
 
return true;
}
 
#region Events
private void SizingGripMouseMove(object sender, MouseEventArgs e) {
if (e.Button == MouseButtons.Left) {
int TvWidth, TvHeight;
TvWidth = Cursor.Position.X - this.frmTreeView.Location.X;
TvWidth = TvWidth + this.DragOffset.X;
TvHeight = Cursor.Position.Y - this.frmTreeView.Location.Y;
TvHeight = TvHeight + this.DragOffset.Y;
 
if (TvWidth < this.Width)
TvWidth = this.Width;
if (TvHeight < this._dropDownHeight)
TvHeight = this._dropDownHeight;
 
this.frmTreeView.Size = new System.Drawing.Size(TvWidth, TvHeight);
this.pnlTree.Size = this.frmTreeView.Size;
this.tvTreeView.Size = new System.Drawing.Size(this.frmTreeView.Size.Width - this.lblSizingGrip.Width, this.frmTreeView.Size.Height - this.lblSizingGrip.Width); ;
RelocateGrip();
}
}
 
private void SizingGripMouseDown(object sender, MouseEventArgs e) {
if (e.Button == MouseButtons.Left) {
int OffsetX = System.Math.Abs(Cursor.Position.X - this.frmTreeView.RectangleToScreen(this.frmTreeView.ClientRectangle).Right);
int OffsetY = System.Math.Abs(Cursor.Position.Y - this.frmTreeView.RectangleToScreen(this.frmTreeView.ClientRectangle).Bottom);
 
this.DragOffset = new Point(OffsetX, OffsetY);
}
}
 
private void TreeViewLostFocus(object sender, EventArgs e) {
if (!this.btnSelect.RectangleToScreen(this.btnSelect.ClientRectangle).Contains(Cursor.Position))
this.frmTreeView.Hide();
}
 
private void TreeViewNodeSelect(object sender, EventArgs e) {
if (this._absoluteChildrenSelectableOnly) {
if (this.tvTreeView.SelectedNode.Nodes.Count == 0) {
tbSelectedValue.Text = this.tvTreeView.SelectedNode.FullPath.Replace(@"\", this._branchSeparator);
this.ToggleTreeView(sender, null);
}
} else {
tbSelectedValue.Text = this.tvTreeView.SelectedNode.FullPath.Replace(@"\", this._branchSeparator);
this.ToggleTreeView(sender, null);
}
}
 
private void InitializeComponent() {
//
// ComboBoxTree
//
this.Name = "ComboBoxTree";
this._absoluteChildrenSelectableOnly = true;
this._dropDownHeight = 106;
this._branchSeparator = "-";
this.Layout += new System.Windows.Forms.LayoutEventHandler(this.ComboBoxTree_Layout);
}
 
private void ComboBoxTree_Layout(object sender, System.Windows.Forms.LayoutEventArgs e) {
this.Height = this.tbSelectedValue.Height + 10;
this.pnlBack.Size = new Size(this.Width, this.Height - 2);
 
this.btnSelect.Size = new Size(16, this.Height - 6);
this.btnSelect.Location = new Point(this.Width - this.btnSelect.Width - 4, 0);
 
this.tbSelectedValue.Location = new Point(2, 2);
this.tbSelectedValue.Width = this.Width - this.btnSelect.Width - 4;
 
this.tvTreeView.Height = this._dropDownHeight;
this.frmTreeView.Size = new Size(this.Width, this.tvTreeView.Height);
this.pnlTree.Size = this.frmTreeView.Size;
this.tvTreeView.Width = this.frmTreeView.Width - this.lblSizingGrip.Width;
this.tvTreeView.Height = this.frmTreeView.Height - this.lblSizingGrip.Width;
this.RelocateGrip();
}
#endregion
 
#region LabelEx
private class LabelEx : Label {
///
///
///

public LabelEx() {
this.SetStyle(ControlStyles.UserPaint, true);
this.SetStyle(ControlStyles.DoubleBuffer, true);
this.SetStyle(ControlStyles.AllPaintingInWmPaint, true);
}
 
///
///
///

///
protected override void OnPaint(PaintEventArgs e) {
base.OnPaint(e);
System.Windows.Forms.ControlPaint.DrawSizeGrip(e.Graphics, System.Drawing.Color.Black, 1, 0, this.Size.Width, this.Size.Height);
}
}
#endregion
 
#region ButtonEx
private class ButtonEx : Button {
ButtonState state;
 
///
///
///

public ButtonEx() {
this.SetStyle(ControlStyles.UserPaint, true);
this.SetStyle(ControlStyles.DoubleBuffer, true);
this.SetStyle(ControlStyles.AllPaintingInWmPaint, true);
 
}
///
///
///

///
protected override void OnMouseDown(MouseEventArgs e) {
state = ButtonState.Pushed;
base.OnMouseDown(e);
}
 
///
///
///

///
protected override void OnMouseUp(MouseEventArgs e) {
state = ButtonState.Normal;
base.OnMouseUp(e);
}
 
///
///
///

///
protected override void OnPaint(PaintEventArgs e) {
base.OnPaint(e);
System.Windows.Forms.ControlPaint.DrawComboButton(e.Graphics, 0, 0, this.Width, this.Height, state);
}
}
#endregion
}
}

GeneralFlatStyle System Pinmemberjake07223-Aug-07 11:30 
GeneralRe: FlatStyle System PinmemberLAcike@sk1-Jul-08 0:40 
GeneralAfterSelect event Pinmembermayank_max104-Jun-07 7:50 
GeneralRe: AfterSelect event Pinmembermayank_max4-Jun-07 10:07 
GeneralRe: AfterSelect event Pinmembermayank_max4-Jun-07 10:13 
GeneralRe: AfterSelect event PinmemberJossGP12-Oct-07 0:41 
QuestionHow to sort the ComboBoxTree Pinmembersatisht23-May-07 21:18 
GeneralNeed this in VB.net [modified] - no longer needed PinmemberVortran9-Oct-06 11:51 
GeneralBug Deteced !! PinmemberH1berto Ferreira3-Jan-06 2:44 
Generalform lostfocus problem PinmemberTurboWang10-Mar-04 15:50 
GeneralRe: form lostfocus problem PinmemberGabe Anguiano12-Mar-04 10:59 
GeneralExcellent ! PinmemberBillWoodruff10-Feb-04 16:52 
GeneralButton on title bar Pinmembersylvain22223-Feb-04 4:05 
GeneralRe: Button on title bar Pinmemberasm433-Feb-04 8:10 
GeneralRe: Button on title bar PinmemberGabe Anguiano3-Feb-04 12:46 
GeneralYou can find many useful ideas in my control too :) PinmemberAlex Kucherenko2-Feb-04 22:51 
GeneralRe: You can find many useful ideas in my control too :) PinmemberGabe Anguiano3-Feb-04 12:40 
Generalnice functionality except you have to select end node PinmemberAshley van Gerven28-Jan-04 22:47 
GeneralRe: nice functionality except you have to select end node PinsussGabe Anguiano (obsidience)29-Jan-04 8:23 

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Article Copyright 2004 by Gabe Anguiano
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