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

namespace WinImageSample
{
    [FlagsAttribute]
    public enum CheckBoxState
    {
        Unchecked = 1,
        Checked = 2,
        Indeterminate = CheckBoxState.Unchecked | CheckBoxState.Checked
    }

    /// <summary>
    /// ThreeStateTreeNode inherits from <see cref="http://msdn2.microsoft.com/en-us/library/sc9ba94b(vs.80).aspx">TreeView</see>
    /// and adds the ability to cascade state changes to related nodes, i.e. child nodes and or parent nodes, as well as to optionally
    /// use the three state functionality.
    /// </summary>
    public class ThreeStateTreeView : TreeView
    {
        ImageList _imageList;
        private bool bHandleCreated = false;
        #region Constructors
        /// <summary>
        /// Initializes a new instance of the ThreeStateTreeView class in addition to intializing
        /// the base class (<see cref="http://msdn2.microsoft.com/en-us/library/system.windows.forms.treeview.treeview(VS.80).aspx">TreeView Constructor</see>). 
        /// </summary>
        public ThreeStateTreeView()
            : base()
        {
            InitializeComponent();
            base.CheckBoxes = true;
            _imageList = new ImageList();
            _imageList.ImageSize = new Size(16, 16);
            if (!NativeMethods.VisualStylesEnabled()) { _imageList = ilChecks; }
            else
            {
                _imageList.Images.Add(ilChecks.Images["Checked0"]);
                UXTheme.LoadCheckBoxImage(_imageList, UXTheme.CheckBoxState.UncheckedNormal);
                UXTheme.LoadCheckBoxImage(_imageList, UXTheme.CheckBoxState.CheckedNormal);
                UXTheme.LoadCheckBoxImage(_imageList, UXTheme.CheckBoxState.MixedNormal);
            }
        }
        #endregion

        private ImageList ilChecks;
        private IContainer components;



        #region Public Properties
        /// <summary>
        /// Flag. If true, use three state checkboxes, otherwise, use the default behavior of the TreeView and associated TreeNodes.
        /// </summary>
        private bool mUseThreeStateCheckBoxes = true;
        [Category("Three State TreeView"),
        Description("Flag. If true, use three state checkboxes, otherwise, use the default behavior of the TreeView and associated TreeNodes."),
        DefaultValue(true),
        TypeConverter(typeof(bool)),
        Editor("System.Boolean", typeof(bool))]
        public bool UseThreeStateCheckBoxes
        {
            get { return this.mUseThreeStateCheckBoxes; }
            set { this.mUseThreeStateCheckBoxes = value; }
        }
        #endregion

        #region Overrides
        public new ImageList ImageList
        {
            get { return base.ImageList; }
            set
            {
                base.ImageList = value;
                this.SetCheckImageList();
            }
        }
        /// <summary>
        /// Raises the AfterCheck event.
        /// </summary>
        /// <param name="e">A <see cref="http://msdn2.microsoft.com/en-us/library/system.windows.forms.treevieweventargs.aspx">TreeViewEventArgs</see> containing the event data.</param>
        protected override void OnAfterCheck(TreeViewEventArgs e)
        {

            if (this.UseThreeStateCheckBoxes)
            {
                switch (e.Action)
                {
                    case TreeViewAction.ByKeyboard:
                    case TreeViewAction.ByMouse:
                        {
                            if (e.Node is ThreeStateTreeNode)
                            {
                                // Toggle to the next state.
                                ThreeStateTreeNode tn = e.Node as ThreeStateTreeNode;
                                tn.Toggle();
                            }

                            break;
                        }
                    case TreeViewAction.Collapse:
                    case TreeViewAction.Expand:
                    case TreeViewAction.Unknown:
                    default:
                        {
                            // Do nothing.
                            break;
                        }
                }
            }
            base.OnAfterCheck(e);
        }
        protected override void OnHandleCreated(EventArgs e)
        {
            base.OnHandleCreated(e);
            bHandleCreated = true;
            SetCheckImageList();
        }
        #endregion
        #region Hide no longer appropriate properties from Designer
        [Browsable(false)]
        public new bool CheckBoxes
        {
            get { return base.CheckBoxes; }
            internal set { base.CheckBoxes = value; }
        }
        [Browsable(false)]
        public new int ImageIndex
        {
            get { return base.ImageIndex; }
            set { base.ImageIndex = value; }
        }
        [Browsable(false)]
        public new int SelectedImageIndex
        {
            get { return base.SelectedImageIndex; }
            set { base.SelectedImageIndex = value; }
        }
        [Browsable(false)]
        public new ImageList StateImageList
        {
            get { return base.StateImageList; }
            internal set { base.StateImageList = value; }
        }
        #endregion

        private void InitializeComponent()
        {
            this.components = new System.ComponentModel.Container();
            System.ComponentModel.ComponentResourceManager resources = new System.ComponentModel.ComponentResourceManager(typeof(ThreeStateTreeView));
            this.ilChecks = new System.Windows.Forms.ImageList(this.components);
            this.SuspendLayout();
            // 
            // ilChecks
            // 
            this.ilChecks.ImageStream = ((System.Windows.Forms.ImageListStreamer)(resources.GetObject("ilChecks.ImageStream")));
            this.ilChecks.TransparentColor = System.Drawing.Color.Transparent;
            this.ilChecks.Images.SetKeyName(0, "Checked0");
            this.ilChecks.Images.SetKeyName(1, "Checked1");
            this.ilChecks.Images.SetKeyName(2, "Checked2");
            this.ilChecks.Images.SetKeyName(3, "Checked3");
            this.ResumeLayout(false);

        }
        private void SetCheckImageList()
        {
            if (!bHandleCreated) return;
            NativeMethods.SendMessage(
                    new HandleRef(this, this.Handle),
                    (int)NativeMethods.Messages.TVM_SETIMAGELIST,
                    (int)NativeMethods.TreeViewImageListType.TVSIL_STATE,
                    (int)_imageList.Handle);
        }
    }

    /// <summary>
    /// ThreeStateTreeNode inherits from <see cref="http://msdn2.microsoft.com/en-us/library/system.windows.forms.treenode.aspx">TreeNode</see>
    /// and adds the ability to support a third, indeterminate state as well as optionally cascading state changes to related nodes, i.e.
    /// child nodes and or parent nodes, as determined by this instance's related parent TreeView settings, CascadeNodeChecksToChildNodes and
    /// CascadeNodeChecksToParentNode.
    /// </summary>
    public class ThreeStateTreeNode : TreeNode
    {
        #region Constructors
        /// <summary>
        /// Initializes a new instance of the ThreeStateTreeNode class in addition to intializing
        /// the base class (<see cref="http://msdn2.microsoft.com/en-us/library/bk8h64c9.aspx">TreeNode Constructor</see>). 
        /// </summary>
        public ThreeStateTreeNode()
            : base()
        {
            this.CommonConstructor();
        }

        /// <summary>
        /// Initializes a new instance of the ThreeStateTreeNode class with a string for the text label to display in addition to intializing
        /// the base class (<see cref="http://msdn2.microsoft.com/en-us/library/ytx906df.aspx">TreeNode Constructor</see>). 
        /// </summary>
        /// <param name="text">The string for the label of the new tree node.</param>
        public ThreeStateTreeNode(string text)
            : base(text)
        {
            this.CommonConstructor();
        }

        /// <summary>
        /// Initializes a new instance of the ThreeStateTreeNode class with a string for the text label to display 
        /// and an array of child ThreeStateTreeNodes in addition to intializing the base class 
        /// (<see cref="http://msdn2.microsoft.com/en-us/library/774ty506.aspx">TreeNode Constructor</see>). 
        /// </summary>
        /// <param name="text">The string for the label of the new tree node.</param>
        /// <param name="children">An array of child ThreeStateTreeNodes.</param>
        public ThreeStateTreeNode(string text, ThreeStateTreeNode[] children)
            : base(text, children)
        {
            this.CommonConstructor();
        }

        /// <summary>
        /// Initializes a new instance of the ThreeStateTreeNode class with a string for the text label to display 
        /// and the selected and unselected image indexes in addition to intializing the base class 
        /// (<see cref="http://msdn2.microsoft.com/en-us/library/8dfy3k5t.aspx">TreeNode Constructor</see>). 
        /// </summary>
        /// <param name="text">The string for the label of the new tree node.</param>
        /// <param name="imageIndex">The image index of the unselected image in the parent TreeView's <see cref="http://msdn2.microsoft.com/en-us/library/system.windows.forms.treeview.imagelist.aspx">ImageList</see>.</param>
        /// <param name="selectedImageIndex">The image index of the selected image in the parent TreeView's <see cref="http://msdn2.microsoft.com/en-us/library/system.windows.forms.treeview.imagelist.aspx">ImageList</see>.</param>
        public ThreeStateTreeNode(string text, int imageIndex, int selectedImageIndex)
            : base(text, imageIndex, selectedImageIndex)
        {
            this.CommonConstructor();
        }

        /// <summary>
        /// Initializes a new instance of the ThreeStateTreeNode class with a string for the text label to display ,
        /// the selected and unselected image indexes, and an array of child ThreeStateTreeNodes in addition to intializing the base class 
        /// (<see cref="http://msdn2.microsoft.com/en-us/library/8dfy3k5t.aspx">TreeNode Constructor</see>). 
        /// </summary>
        /// <param name="text">The string for the label of the new tree node.</param>
        /// <param name="imageIndex">The image index of the unselected image in the parent TreeView's <see cref="http://msdn2.microsoft.com/en-us/library/system.windows.forms.treeview.imagelist.aspx">ImageList</see>.</param>
        /// <param name="selectedImageIndex">The image index of the selected image in the parent TreeView's <see cref="http://msdn2.microsoft.com/en-us/library/system.windows.forms.treeview.imagelist.aspx">ImageList</see>.</param>
        /// <param name="children">An array of child ThreeStateTreeNodes.</param>
        public ThreeStateTreeNode(string text, int imageIndex, int selectedImageIndex, ThreeStateTreeNode[] children)
            : base(text, imageIndex, selectedImageIndex, children)
        {
            this.CommonConstructor();
        }
        #endregion

        #region Initialization
        /// <summary>
        /// Performs common initialization to all constructors.
        /// </summary>
        private void CommonConstructor()
        {
        }
        #endregion

        #region Properties
        /// <summary>
        /// The current state of the checkbox.
        /// </summary>
        private CheckBoxState mState = CheckBoxState.Unchecked;
        [Category("Three State TreeView"),
        Description("The current state of the node's checkbox, Unchecked, Checked, or Indeterminate"),
        DefaultValue(CheckBoxState.Unchecked),
        TypeConverter(typeof(CheckBoxState)),
        Editor("Ascentium.Research.Windows.Components.CheckBoxState", typeof(CheckBoxState))]
        public CheckBoxState State
        {
            get { return this.mState; }
            set
            {
                if (this.mState != value)
                {
                    this.mState = value;

                    // Ensure if checkboxes are used to make the checkbox checked or unchecked.
                    // When go to a fully drawn control, this will be managed in the drawing code.
                    // Setting the Checked property in code will cause the OnAfterCheck to be called
                    // and the action will be 'Unknown'; do not handle that case.
                    //if ((this.TreeView != null) && (this.TreeView.CheckBoxes))
                    //    this.Checked = (this.mState == CheckBoxState.Checked);

                    SetState(value);
                }
            }
        }

        /// <summary>
        /// Returns the 'combined' state for all siblings of a node.
        /// </summary>
        private CheckBoxState SiblingsState
        {
            get
            {
                // If parent is null, cannot have any siblings or if the parent
                // has only one child (i.e. this node) then return the state of this 
                // instance as the state.
                if ((this.Parent == null) || (this.Parent.Nodes.Count == 1))
                    return this.State;

                // The parent has more than one child.  Walk through parent's child
                // nodes to determine the state of all this node's siblings,
                // including this node.
                CheckBoxState state = 0;
                foreach (TreeNode node in this.Parent.Nodes)
                {
                    ThreeStateTreeNode child = node as ThreeStateTreeNode;
                    if (child != null)
                        state |= child.State;

                    // If the state is now indeterminate then know there
                    // is a combination of checked and unchecked nodes
                    // and no longer need to continue evaluating the rest
                    // of the sibling nodes.
                    if (state == CheckBoxState.Indeterminate)
                        break;
                }

                return (state == 0) ? CheckBoxState.Unchecked : state;
            }
        }

        #endregion

        #region Methods
        /// <summary>
        /// Manages state changes from one state to the next.
        /// </summary>
        /// <param name="fromState">The state upon which to base the state change.</param>
        public void Toggle(CheckBoxState fromState)
        {
            switch (fromState)
            {
                case CheckBoxState.Indeterminate:
                case CheckBoxState.Unchecked:
                    {
                        this.State = CheckBoxState.Checked;
                        break;
                    }
                case CheckBoxState.Checked:
                default:
                    {
                        this.State = CheckBoxState.Unchecked;
                        break;
                    }
            }

            this.UpdateStateOfRelatedNodes();
        }

        /// <summary>
        /// Manages state changes from one state to the next.
        /// </summary>
        public new void Toggle() { this.Toggle(this.State); }

        /// <summary>
        /// Manages updating related child and parent nodes of this instance.
        /// </summary>
        public void UpdateStateOfRelatedNodes()
        {
            ThreeStateTreeView tv = this.TreeView as ThreeStateTreeView;
            if ((tv != null) && tv.CheckBoxes && tv.UseThreeStateCheckBoxes)
            {
                tv.BeginUpdate();

                // If want to cascade checkbox state changes to child nodes of this node and
                // if the current state is not intermediate, update the state of child nodes.
                if (this.State != CheckBoxState.Indeterminate)