c# Winforms Treeview自定义复选框

好了，不好意思，好久不见。你知道，生活之类的。总之，我最终创建了自己的TreeNode和TreeView类。这是我第一次使用WinForms，所以很多东西看起来都很挑剔。结果比我想象的要简单得多。如果有人想用这个，请自便。

Check*.bmp图像只是一个我上色的复选框。我可能会为此制作自己的四个图像，并整理populateStateImageList()方法。此外，我认为这将适用于您需要的尽可能多的状态，直到StateImageList的14个图像限制。

using System.Drawing;
using System.Windows.Forms;
namespace jkHTMLBuilder
{
    public class QuadCheckTreeNode : TreeNode
    {
        public enum CheckState : int { UnChecked, Checked, Chair, Rank }    // The four possible states
        private CheckState _cs = CheckState.UnChecked;                      // The node's current state
        public CheckState checkState
        {
            get
            {
                return _cs;
            }
            set
            {
                _cs = value;
            }
        }
        public QuadCheckTreeNode(string initString) : base()
        {
            this.Text = initString;
            this.checkState = CheckState.UnChecked;
            this.Checked = false;
            this.StateImageIndex = 0;
        }
        public void checkAdvance()                                          // This is called from onAfterCheck to set the next consecutive state
        {
            switch (checkState)
            {
                case CheckState.UnChecked:
                    checkState = CheckState.Checked;
                    break;
                case CheckState.Checked:
                    checkState = CheckState.Chair;
                    break;
                case CheckState.Chair:
                    checkState = CheckState.Rank;
                    break;
                case CheckState.Rank:
                    checkState = CheckState.UnChecked;
                    break;
            }
            this.Checked = (this.checkState == CheckState.UnChecked ? false : true);
        }
    }
    class QuadCheckTreeView : TreeView
    {
        private bool clickStop = false;
        private bool shouldAdvance = false;
        public QuadCheckTreeView() : base()
        {
            StateImageList = new ImageList();
        }
        public void populateStateImageList()                                // I made this a separate method and call it from my Load_Senators method so the images are
        {                                                                   // set up when the XML file is loaded.  Apparently, loading the files ( Check*.bmmp )
            for (int i = 0; i < 2; i++)                                     // from the ctor causes problems...?  Whatever.  This works.
            {
                Bitmap bmp = new Bitmap(16, 16);
                Graphics chkGraphics = Graphics.FromImage(bmp);
                switch (i)
                {
                    case 0:
                        CheckBoxRenderer.DrawCheckBox(chkGraphics, new Point(0, 1), System.Windows.Forms.VisualStyles.CheckBoxState.UncheckedNormal);
                        break;
                    case 1:
                        CheckBoxRenderer.DrawCheckBox(chkGraphics, new Point(0, 1), System.Windows.Forms.VisualStyles.CheckBoxState.CheckedNormal);
                        break;
                }
                StateImageList.Images.Add(bmp);
            }
            Bitmap myBitmap = new Bitmap("..''..''CheckBlue.bmp");
            StateImageList.Images.Add(myBitmap);
            myBitmap = new Bitmap("..''..''CheckRed.bmp");
            StateImageList.Images.Add(myBitmap);
        }                               
        public void ClearNodes(TreeNodeCollection nodes)                    // This is for when I move on to the next record.  Unchecks everything.
        {
            clickStop = true;
            foreach (QuadCheckTreeNode qctn in nodes)
            {
                qctn.Checked = false;
                qctn.checkState = QuadCheckTreeNode.CheckState.UnChecked;
                if (qctn.Nodes.Count > 0)
                {
                    foreach (QuadCheckTreeNode cqctn in qctn.Nodes)
                    {
                        cqctn.Checked = false;
                        cqctn.checkState = QuadCheckTreeNode.CheckState.UnChecked;
                    }
                }
            }
            clickStop = false;
        }
        protected override void OnCreateControl()
        {
            base.OnCreateControl();
            CheckBoxes = false;                                             // Checkboxes off to use my images
            ClearNodes(this.Nodes);                                         // Probably not needed.
        }
        protected override void OnNodeMouseClick(TreeNodeMouseClickEventArgs e)
        {
            base.OnNodeMouseClick(e);
            TreeViewHitTestInfo tvhtInfo = HitTest(e.X, e.Y);               // If you didn't click on it, ignore.
            if (tvhtInfo == null || tvhtInfo.Location !=
            TreeViewHitTestLocations.StateImage)
            {
                return;
            }
            QuadCheckTreeNode qctn = (QuadCheckTreeNode)e.Node;             // If you right-clicked, set to UnChecked
            if (e.Button == MouseButtons.Right)
            {
                if (qctn.checkState != QuadCheckTreeNode.CheckState.UnChecked)
                {
                    qctn.checkState = QuadCheckTreeNode.CheckState.UnChecked;
                    qctn.Checked = false;
                    shouldAdvance = false;
                }
            }
            else
                shouldAdvance = true;                                       // Left click sets this var==true so the node's Advance() method is called
            qctn.Checked = qctn.Checked;                                    // This fires the onAfterCheck event
        }
        protected override void OnAfterCheck(TreeViewEventArgs e)
        {
            base.OnAfterCheck(e);
            if (clickStop)                                                  // This keeps the event from running if it's called inappropriately
            {
                return;
            }
            clickStop = true;
            QuadCheckTreeNode qctn = (QuadCheckTreeNode)e.Node;
            if (shouldAdvance)
            {
                qctn.checkAdvance();
                shouldAdvance = false;
                qctn.StateImageIndex = (int)qctn.checkState;
            }
            checkParent(qctn);                                              // Calling this method, if it actually checks a parent node, won't call onAfterCheck because of clickStop
            clickStop = false;
        }
        protected void checkParent(QuadCheckTreeNode qctn)
        {
            QuadCheckTreeNode pqctn = (QuadCheckTreeNode)qctn.Parent;
            if (pqctn == null)
                return;
            if (pqctn.checkState == QuadCheckTreeNode.CheckState.UnChecked) // This checks a parent if it has a checked child
            {
                bool chkParent = false;
                foreach (QuadCheckTreeNode n in pqctn.Nodes)
                {
                    if (n.checkState != QuadCheckTreeNode.CheckState.UnChecked)     // Checks all the children.  If even one is checked, the parent gets checked
                        chkParent = true;
                }
                if (chkParent)
                {
                    pqctn.Checked = true;
                    pqctn.checkState = QuadCheckTreeNode.CheckState.Checked;
                }
            }
        }
    }
}