Tri-State TreeView Control

Private Sub FillTreeView()

    Try
        With tvRooms
            .BeginUpdate()
            .Nodes.Clear()
            For Each drRoom As DataRow In HouseholdInventoryDataSet.Tables("Rooms").Rows
                'Adds the room as a root node
                Dim nodParent As TreeNode
                nodParent = tvRooms.Nodes.Add(drRoom.Item("Room").ToString)
                nodParent.Tag = drRoom.Item("Room").ToString
                For Each drItem As DataRow In drRoom.GetChildRows(HouseholdInventoryDataSet.Relations("Rooms_Inventory"))
                    'Adds the inventory item as child of the room
                    Dim nodChild As TreeNode
                    nodChild = nodParent.Nodes.Add(drItem.Item("ItemName").ToString)
                    nodChild.Tag = drItem.Item("ID")
                Next drItem
            Next drRoom
            If tvRooms.Nodes.Count = 0 Then Exit Sub
            .ExpandAll()
            .Nodes(0).EnsureVisible()
            .EndUpdate()
        End With

    Catch ex As Exception
        gMsg = "The following error occurred filling the tree view: " + vbCrLf + ex.Message
        MsgBox(gMsg)
    End Try
End Sub

// ---------------------------------------------------------------------------------------------<br />
#region // Copyright (c) 2004-2005, SIL International. All Rights Reserved.   <br />
// <copyright from='2004' to='2005' company='SIL International'><br />
//		Copyright (c) 2004-2005, SIL International. All Rights Reserved.   <br />
//    <br />
//		Distributable under the terms of either the Common Public License or the<br />
//		GNU Lesser General Public License, as specified in the LICENSING.txt file.<br />
// </copyright> <br />
#endregion<br />
// <br />
// File: TriStateTreeView.cs<br />
// Responsibility: Eberhard Beilharz/Tim Steenwyk<br />
// <br />
// <remarks><br />
// Downloaded from the CodeProject, at http://www.codeproject.com/KB/tree/TriStateTreeViewSubmissio.aspx?msg=3054765#xx3054765xx<br />
// </remarks><br />
// ---------------------------------------------------------------------------------------------<br />
using System;<br />
using System.Collections;<br />
using System.ComponentModel;<br />
using System.Drawing;<br />
using System.Data;<br />
using System.Runtime.InteropServices;<br />
using System.Windows.Forms;<br />
using System.Runtime.Serialization;<br />
<br />
namespace WinControls<br />
{<br />
	/// ----------------------------------------------------------------------------------------<br />
	/// <summary><br />
	/// A tree view with tri-state check boxes<br />
	/// </summary><br />
	/// <remarks><br />
	/// REVIEW: If we want to have icons in addition to the check boxes, we probably have to <br />
	/// set the icons for the check boxes in a different way. The windows tree view control<br />
	/// can have a separate image list for states.<br />
	/// </remarks><br />
	/// ----------------------------------------------------------------------------------------<br />
	public class TriStateTreeView : TreeView<br />
	{<br />
      private System.Drawing.Color mDisabledNodeColor;<br />
<br />
      /// <summary><br />
      /// Gets/sets the color of the disabled nodes. Used to tell if a node should be checked off or not.<br />
      /// </summary><br />
      public System.Drawing.Color DisabledNodeColor<br />
      {<br />
         get { return mDisabledNodeColor; }<br />
         set { mDisabledNodeColor = value; }<br />
      }<br />
	<br />
		private System.Windows.Forms.ImageList m_TriStateImages;<br />
		private System.ComponentModel.IContainer components;<br />
		/// <summary><br />
		/// The check state<br />
		/// </summary><br />
		/// <remarks>The states corresponds to image index</remarks><br />
		public enum CheckState<br />
		{<br />
			/// <summary>greyed out</summary><br />
			GreyChecked = 0,<br />
			/// <summary>Unchecked</summary><br />
			Unchecked = 1,<br />
			/// <summary>Checked</summary><br />
			Checked = 2,<br />
		}<br />
<br />
		#region Redefined Win-API structs and methods<br />
		/// <summary></summary><br />
		[StructLayout(LayoutKind.Sequential, Pack=1)]<br />
			public struct TV_HITTESTINFO<br />
		{<br />
			/// <summary>Client coordinates of the point to test.</summary><br />
			public Point pt;<br />
			/// <summary>Variable that receives information about the results of a hit test.</summary><br />
			public TVHit flags;<br />
			/// <summary>Handle to the item that occupies the point.</summary><br />
			public IntPtr hItem;<br />
		}<br />
<br />
		/// <summary>Hit tests for tree view</summary><br />
		[Flags]<br />
		public enum TVHit<br />
		{<br />
			/// <summary>In the client area, but below the last item.</summary><br />
			NoWhere = 0x0001,<br />
			/// <summary>On the bitmap associated with an item.</summary><br />
			OnItemIcon = 0x0002,<br />
			/// <summary>On the label (string) associated with an item.</summary><br />
			OnItemLabel = 0x0004,<br />
			/// <summary>In the indentation associated with an item.</summary><br />
			OnItemIndent = 0x0008,<br />
			/// <summary>On the button associated with an item.</summary><br />
			OnItemButton = 0x0010,<br />
			/// <summary>In the area to the right of an item. </summary><br />
			OnItemRight = 0x0020,<br />
			/// <summary>On the state icon for a tree-view item that is in a user-defined state.</summary><br />
			OnItemStateIcon = 0x0040,<br />
			/// <summary>On the bitmap or label associated with an item. </summary><br />
			OnItem = (OnItemIcon | OnItemLabel | OnItemStateIcon),<br />
			/// <summary>Above the client area. </summary><br />
			Above = 0x0100,<br />
			/// <summary>Below the client area.</summary><br />
			Below = 0x0200,<br />
			/// <summary>To the right of the client area.</summary><br />
			ToRight = 0x0400,<br />
			/// <summary>To the left of the client area.</summary><br />
			ToLeft = 0x0800<br />
		}<br />
<br />
		/// <summary></summary><br />
		public enum TreeViewMessages<br />
		{<br />
			/// <summary></summary><br />
			TV_FIRST            = 0x1100,      // TreeView messages<br />
			/// <summary></summary><br />
			TVM_HITTEST         = (TV_FIRST + 17),<br />
		}<br />
<br />
		/// <summary></summary><br />
		[DllImport("user32.dll", CharSet=CharSet.Auto)]<br />
		public static extern int SendMessage(IntPtr hWnd, TreeViewMessages msg, int wParam, ref TV_HITTESTINFO lParam);<br />
		#endregion<br />
<br />
		#region Constructor and destructor<br />
		/// ------------------------------------------------------------------------------------<br />
		/// <summary><br />
		/// Initializes a new instance of the <see cref="TriStateTreeView"/> class.<br />
		/// </summary><br />
		/// ------------------------------------------------------------------------------------<br />
		public TriStateTreeView()<br />
		{<br />
			// This call is required by the Windows.Forms Form Designer.<br />
			InitializeComponent();<br />
         mDisabledNodeColor = SystemColors.GrayText;<br />
			ImageList = m_TriStateImages;<br />
			ImageIndex = (int)CheckState.Unchecked;<br />
			SelectedImageIndex = (int)CheckState.Unchecked;<br />
		}<br />
<br />
		/// -----------------------------------------------------------------------------------<br />
		/// <summary> <br />
		/// Clean up any resources being used.<br />
		/// </summary><br />
		/// <param name="disposing"><c>true</c> to release both managed and unmanaged <br />
		/// resources; <c>false</c> to release only unmanaged resources. <br />
		/// </param><br />
		/// -----------------------------------------------------------------------------------<br />
		protected override void Dispose( bool disposing )<br />
		{<br />
			if( disposing )<br />
			{<br />
				if(components != null)<br />
				{<br />
					components.Dispose();<br />
				}<br />
			}<br />
			base.Dispose( disposing );<br />
		}<br />
		#endregion<br />
<br />
		#region Component Designer generated code<br />
		/// -----------------------------------------------------------------------------------<br />
		/// <summary> <br />
		/// Required method for Designer support - do not modify <br />
		/// the contents of this method with the code editor.<br />
		/// </summary><br />
		/// -----------------------------------------------------------------------------------<br />
		private void InitializeComponent()<br />
		{<br />
			this.components = new System.ComponentModel.Container();<br />
			System.Resources.ResourceManager resources = new System.Resources.ResourceManager(typeof(TriStateTreeView));<br />
			this.m_TriStateImages = new System.Windows.Forms.ImageList(this.components);<br />
			// <br />
			// m_TriStateImages<br />
			// <br />
			this.m_TriStateImages.ImageSize = new System.Drawing.Size(16, 16);<br />
			this.m_TriStateImages.ImageStream = ((System.Windows.Forms.ImageListStreamer)(resources.GetObject("m_TriStateImages.ImageStream")));<br />
			this.m_TriStateImages.TransparentColor = System.Drawing.Color.Magenta;<br />
<br />
		}<br />
		#endregion<br />
<br />
		#region Hide no longer appropriate properties from Designer<br />
		/// ------------------------------------------------------------------------------------<br />
		/// <summary><br />
		/// <br />
		/// </summary><br />
		/// ------------------------------------------------------------------------------------<br />
		[Browsable(false)]<br />
		public new bool CheckBoxes<br />
		{<br />
			get { return base.CheckBoxes; }<br />
			set { base.CheckBoxes = value; }<br />
		}<br />
<br />
		/// ------------------------------------------------------------------------------------<br />
		/// <summary><br />
		/// <br />
		/// </summary><br />
		/// ------------------------------------------------------------------------------------<br />
		[Browsable(false)]<br />
		public new int ImageIndex<br />
		{<br />
			get { return base.ImageIndex; }<br />
			set { base.ImageIndex = value; }<br />
		}<br />
<br />
		/// ------------------------------------------------------------------------------------<br />
		/// <summary><br />
		/// <br />
		/// </summary><br />
		/// ------------------------------------------------------------------------------------<br />
		[Browsable(false)]<br />
		public new ImageList ImageList<br />
		{<br />
			get { return base.ImageList; }<br />
			set { base.ImageList = value; }<br />
		}<br />
<br />
		/// ------------------------------------------------------------------------------------<br />
		/// <summary><br />
		/// <br />
		/// </summary><br />
		/// ------------------------------------------------------------------------------------<br />
		[Browsable(false)]<br />
		public new int SelectedImageIndex<br />
		{<br />
			get { return base.SelectedImageIndex; }<br />
			set { base.SelectedImageIndex = value; }<br />
		}<br />
		#endregion<br />
<br />
		#region Overrides<br />
      /*protected new TriStateTreeNode[] Nodes <br />
      { <br />
         this.nodes<br />
      }*/<br />
		/// ------------------------------------------------------------------------------------<br />
		/// <summary><br />
		/// Called when the user clicks on an item<br />
		/// </summary><br />
		/// <param name="e"></param><br />
		/// ------------------------------------------------------------------------------------<br />
		protected override void OnClick(EventArgs e)<br />
		{<br />
			base.OnClick (e);<br />
<br />
			TV_HITTESTINFO hitTestInfo = new TV_HITTESTINFO();<br />
			hitTestInfo.pt = PointToClient(Control.MousePosition);<br />
<br />
			SendMessage(Handle, TreeViewMessages.TVM_HITTEST,<br />
				0, ref hitTestInfo);<br />
			if ((hitTestInfo.flags & TVHit.OnItemIcon) == TVHit.OnItemIcon)<br />
			{<br />
				TreeNode node = GetNodeAt(hitTestInfo.pt);<br />
            if (node != null)<br />
            {<br />
               ChangeNodeState(node);<br />
            }<br />
			}<br />
		}<br />
<br />
		/// ------------------------------------------------------------------------------------<br />
		/// <summary><br />
		/// Toggle item if user presses space bar<br />
		/// </summary><br />
		/// <param name="e"></param><br />
		/// ------------------------------------------------------------------------------------<br />
		protected override void OnKeyDown(KeyEventArgs e)<br />
		{<br />
			base.OnKeyDown (e);<br />
<br />
			if (e.KeyCode == Keys.Space)<br />
				ChangeNodeState(SelectedNode);<br />
		}<br />
		#endregion<br />
<br />
		#region Private methods<br />
		/// ------------------------------------------------------------------------------------<br />
		/// <summary><br />
		/// Checks or unchecks all children<br />
		/// </summary><br />
		/// <param name="node"></param><br />
		/// <param name="state"></param><br />
		/// ------------------------------------------------------------------------------------<br />
		private void CheckNode(TreeNode node, CheckState state)<br />
		{<br />
			bool checkSet = InternalSetChecked(node, state);<br />
<br />
         if (checkSet)<br />
         {<br />
            foreach (TreeNode child in node.Nodes)<br />
            {<br />
               CheckNode(child, state);<br />
            }<br />
         }<br />
<br />
         ChangeParent(node.Parent);<br />
		}<br />
<br />
		/// ------------------------------------------------------------------------------------<br />
		/// <summary><br />
		/// Called after a node changed its state. Has to go through all direct children and<br />
		/// set state based on children's state.<br />
		/// </summary><br />
		/// <param name="node">Parent node</param><br />
		/// ------------------------------------------------------------------------------------<br />
		private void ChangeParent(TreeNode node)<br />
		{<br />
         if (node == null)<br />
         {<br />
            return;<br />
         }<br />
<br />
			CheckState state = GetChecked(node.FirstNode);<br />
			foreach (TreeNode child in node.Nodes)<br />
				state &= GetChecked(child);<br />
<br />
         if (InternalSetChecked(node, state))<br />
         {<br />
            ChangeParent(node.Parent);<br />
         }<br />
		}<br />
<br />
		/// ------------------------------------------------------------------------------------<br />
		/// <summary><br />
		/// Handles changing the state of a node<br />
		/// </summary><br />
		/// <param name="node"></param><br />
		/// ------------------------------------------------------------------------------------<br />
		protected void ChangeNodeState(TreeNode node)<br />
		{<br />
         if (node.ForeColor != mDisabledNodeColor)<br />
         {<br />
            BeginUpdate();<br />
            CheckState newState;<br />
            if (node.ImageIndex == (int)CheckState.Unchecked || node.ImageIndex < 0)<br />
            {<br />
               newState = CheckState.Checked;<br />
            }<br />
            else<br />
            {<br />
               newState = CheckState.Unchecked;<br />
            }<br />
            CheckNode(node, newState);<br />
            ChangeParent(node.Parent);<br />
            EndUpdate();<br />
         }<br />
		}<br />
<br />
		/// ------------------------------------------------------------------------------------<br />
		/// <summary><br />
		/// Sets the checked state of a node, but doesn't deal with children or parents<br />
		/// </summary><br />
		/// <param name="node">Node</param><br />
		/// <param name="state">The new checked state</param><br />
		/// <returns><c>true</c> if checked state was set to the requested state, otherwise<br />
		/// <c>false</c>.</returns><br />
		/// ------------------------------------------------------------------------------------<br />
		private bool InternalSetChecked(TreeNode node, CheckState state)<br />
		{<br />
         bool returnValue = true;<br />
         if (node.ForeColor != mDisabledNodeColor)<br />
         {<br />
            TreeViewCancelEventArgs args = new TreeViewCancelEventArgs(node, false, TreeViewAction.Unknown);<br />
            OnBeforeCheck(args);<br />
            if (args.Cancel)<br />
            {<br />
               returnValue = false;<br />
            }<br />
<br />
            node.ImageIndex = (int)state;<br />
            node.SelectedImageIndex = (int)state;<br />
<br />
            OnAfterCheck(new TreeViewEventArgs(node, TreeViewAction.Unknown));<br />
         }<br />
         else<br />
         {<br />
            returnValue = false;<br />
         }<br />
         return returnValue;<br />
		}<br />
<br />
		/// ------------------------------------------------------------------------------------<br />
		/// <summary><br />
		/// Build a list of all of the tag data for checked items in the tree.<br />
		/// </summary><br />
		/// <param name="node"></param><br />
		/// <param name="list"></param><br />
		/// ------------------------------------------------------------------------------------<br />
		private void BuildTagDataList(TreeNode node, ArrayList list)<br />
		{<br />
			if (GetChecked(node) == CheckState.Checked && node.Tag != null)<br />
				list.Add(node.Tag);<br />
<br />
			foreach (TreeNode child in node.Nodes)<br />
				BuildTagDataList(child, list);<br />
		}<br />
<br />
		/// ------------------------------------------------------------------------------------<br />
		/// <summary><br />
		/// Look through the tree nodes to find the node that has given tag data and check it.<br />
		/// </summary><br />
		/// <param name="node"></param><br />
		/// <param name="tag"></param><br />
		/// <param name="state"></param><br />
		/// ------------------------------------------------------------------------------------<br />
		private void FindAndCheckNode(TreeNode node, object tag, CheckState state)<br />
		{<br />
			if (node.Tag != null && node.Tag.Equals(tag))<br />
			{<br />
				SetChecked(node, state);<br />
				return;<br />
			}<br />
<br />
			foreach (TreeNode child in node.Nodes)<br />
				FindAndCheckNode(child, tag, state);<br />
		}<br />
		#endregion<br />
<br />
		#region Public methods<br />
      /// ------------------------------------------------------------------------------------<br />
      /// <summary><br />
      /// Gets the checked state of a node<br />
      /// </summary><br />
      /// <param name="nodeName">Node name</param><br />
      /// <returns>The checked state</returns><br />
      /// ------------------------------------------------------------------------------------<br />
      public CheckState GetChecked(string nodeName)<br />
      {<br />
         CheckState returnCheckState = CheckState.GreyChecked;<br />
<br />
         TreeNode[] nodes = this.Nodes.Find(nodeName, true);<br />
         if (nodes != null && nodes.Length > 0)<br />
         {<br />
            returnCheckState = GetChecked(nodes[0]);<br />
         }<br />
         else<br />
         {<br />
            throw new Exception("Node " + nodeName + " not found.");<br />
         }<br />
         return returnCheckState;<br />
      }<br />
<br />
      /// ------------------------------------------------------------------------------------<br />
		/// <summary><br />
		/// Gets the checked state of a node<br />
		/// </summary><br />
		/// <param name="node">Node</param><br />
		/// <returns>The checked state</returns><br />
		/// ------------------------------------------------------------------------------------<br />
		public CheckState GetChecked(TreeNode node)<br />
		{<br />
			if (node.ImageIndex < 0)<br />
				return CheckState.Unchecked;<br />
			else<br />
				return (CheckState)node.ImageIndex;<br />
		}<br />
<br />
		/// ------------------------------------------------------------------------------------<br />
		/// <summary><br />
		/// Sets the checked state of a node<br />
		/// </summary><br />
		/// <param name="node">Node</param><br />
		/// <param name="state">The new checked state</param><br />
		/// ------------------------------------------------------------------------------------<br />
		public void SetChecked(TreeNode node, CheckState state)<br />
		{<br />
         bool stateChanged = InternalSetChecked(node, state);<br />
<br />
         if (stateChanged)<br />
         {<br />
            CheckNode(node, state);<br />
         }<br />
			ChangeParent(node.Parent);<br />
		}<br />
<br />
		/// ------------------------------------------------------------------------------------<br />
		/// <summary><br />
		/// Find a node in the tree that matches the given tag data and set its checked state<br />
		/// </summary><br />
		/// <param name="tag"></param><br />
		/// <param name="state"></param><br />
		/// ------------------------------------------------------------------------------------<br />
		public void CheckNodeByTag(object tag, CheckState state)<br />
		{<br />
			if (tag == null)<br />
				return;<br />
			foreach (TreeNode node in Nodes)<br />
				FindAndCheckNode(node, tag, state);<br />
		}<br />
<br />
		/// ------------------------------------------------------------------------------------<br />
		/// <summary><br />
		/// Return a list of the tag data for all of the checked items in the tree<br />
		/// </summary><br />
		/// <returns></returns><br />
		/// ------------------------------------------------------------------------------------<br />
		public ArrayList GetCheckedTagData()<br />
		{<br />
			ArrayList list = new ArrayList();<br />
<br />
			foreach (TreeNode node in Nodes)<br />
				BuildTagDataList(node, list);<br />
			return list;<br />
		}<br />
		#endregion<br />
	}<br />
}<br />