windform 重绘Treeview "+-"号图标

模仿wind系统界面，重绘Treeview + - 号图标

一，首先需要图片 ，用于替换原有的 +-号

二、新建Tree扩展类 TreeViewEx继承TreeView

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

/*******************************************************************
* Copyright (C)  版权所有
* 文件名称:TreeViewEx
* 命名空间:TestRecentMenu
* 创建时间:2018/12/18 16:49:08
* 作    者: wangyonglai
* 描    述：
* 修改记录:
* 修改人:
* 版 本 号:v1.0.0
**********************************************************************/
namespace TestRecentMenu
{
    public class TreeViewEx : TreeView
    {
        private bool ArrowKeyUp = false;
        private bool ArrowKeyDown = false;
        private System.Windows.Forms.ImageList arrowImageList1;

        /*1节点被选中 ,TreeView有焦点*/
        private SolidBrush brush1 = new SolidBrush(Color.FromArgb(209, 232, 255));//填充颜色
        private Pen pen1 = new Pen(Color.FromArgb(102, 167, 232), 1);//边框颜色

        /*2节点被选中 ,TreeView没有焦点*/
        private SolidBrush brush2 = new SolidBrush(Color.FromArgb(247, 247, 247));
        private Pen pen2 = new Pen(Color.FromArgb(222, 222, 222), 1);

        /*3 MouseMove的时候 画光标所在的节点的背景*/
        private SolidBrush brush3 = new SolidBrush(Color.FromArgb(229, 243, 251));
        private Pen pen3 = new Pen(Color.FromArgb(112, 192, 231), 1);

        public const int WM_PRINTCLIENT = 0x0318;
        public const int PRF_CLIENT = 0x00000004;

        //替换+-号图标的imagelist
        public ImageList arrowImageList
        {
            get
            {
                return arrowImageList1;
            }
            set
            {
                arrowImageList1 = value;
            }
        }

        public TreeViewEx()
        {
            //双缓存防止屏幕抖动
            //this.SetStyle(ControlStyles.UserPaint, true);
            this.SetStyle(ControlStyles.OptimizedDoubleBuffer | ControlStyles.AllPaintingInWmPaint | ControlStyles.DoubleBuffer, true);
            this.UpdateStyles();
            this.DrawMode = TreeViewDrawMode.OwnerDrawAll;
            this.FullRowSelect = true;
            this.HotTracking = true;
            this.HideSelection = false;
            this.ShowLines = false;
　　　　　　　this.ShowNodeToolTips = true;
            this.ItemHeight = 20;

        }

        protected override void OnDrawNode(DrawTreeNodeEventArgs e)
        {
            base.OnDrawNode(e);

            #region 1     选中的节点背景=========================================
            Rectangle nodeRect = new Rectangle(1, e.Bounds.Top, e.Bounds.Width - 3, e.Bounds.Height - 1);

            if (e.Node.IsSelected)
            {
                if (this.Focused)
                {
                    e.Graphics.FillRectangle(brush1, nodeRect);
                    e.Graphics.DrawRectangle(pen1, nodeRect);
                }
                else
                {
                    e.Graphics.FillRectangle(brush2, nodeRect);
                    e.Graphics.DrawRectangle(pen2, nodeRect);
                }

            }
            else if ((e.State & TreeNodeStates.Hot) != 0 && e.Node.Text != "")//|| currentMouseMoveNode == e.Node)
            {
                e.Graphics.FillRectangle(brush3, nodeRect);
                e.Graphics.DrawRectangle(pen3, nodeRect);
            }
            else
            {
                e.Graphics.FillRectangle(Brushes.White, e.Bounds);
            }

            #endregion

            #region 2     +-号绘制=========================================
            Rectangle plusRect = new Rectangle(e.Node.Bounds.Left - 32, nodeRect.Top + 6, 9, 9); // +-号的大小 是9 * 9

            if (e.Node.IsExpanded)
                e.Graphics.DrawImage(arrowImageList.Images[1], plusRect);
            else if (e.Node.IsExpanded == false && e.Node.Nodes.Count > 0)
                e.Graphics.DrawImage(arrowImageList.Images[0], plusRect);

            /*测试用 画出+-号出现的矩形*/
            //if (e.Node.Nodes.Count > 0)
            //    e.Graphics.DrawRectangle(new Pen(Color.Red), plusRect);
            #endregion

            #region 3     画节点文本=========================================
            Rectangle nodeTextRect = new Rectangle(
                                                    e.Node.Bounds.Left,
                                                    e.Node.Bounds.Top + 4,
                                                    e.Node.Bounds.Width + 2,
                                                    e.Node.Bounds.Height
                                                    );
            nodeTextRect.Width += 4;
            nodeTextRect.Height -= 4;

            e.Graphics.DrawString(e.Node.Text,
                                  e.Node.TreeView.Font,
                                  new SolidBrush(Color.Black),
                                  nodeTextRect);

            //画子节点个数 (111)
            if (e.Node.GetNodeCount(true) > 0)
            {
                e.Graphics.DrawString(string.Format("({0})", e.Node.GetNodeCount(true)),
                                        new Font("Arial", 8),
                                        Brushes.Gray,
                                        nodeTextRect.Right - 4,
                                        nodeTextRect.Top -2);
            }

            ///*测试用，画文字出现的矩形*/
            //if (e.Node.Text != "")
            //    e.Graphics.DrawRectangle(new Pen(Color.Blue), nodeTextRect);
            #endregion

            #region 4   画IImageList 中的图标===================================================================

            int currt_X = e.Node.Bounds.X;
            if (this.ImageList != null && this.ImageList.Images.Count > 0)
            {
                //图标大小16*16
                Rectangle imagebox = new Rectangle(
                    e.Node.Bounds.X - 3 - 16,
                    e.Node.Bounds.Y + 2,
                    16,//IMAGELIST IMAGE WIDTH
                    16);//HEIGHT

                int index = e.Node.ImageIndex;
                string imagekey = e.Node.ImageKey;
                if (imagekey != "" && this.ImageList.Images.ContainsKey(imagekey))
                    e.Graphics.DrawImage(this.ImageList.Images[imagekey], imagebox);
                else
                {
                    if (e.Node.ImageIndex < 0)
                        index = 0;
                    else if (index > this.ImageList.Images.Count - 1)
                        index = 0;
                    e.Graphics.DrawImage(this.ImageList.Images[index], imagebox);
                }
                currt_X -= 19;

                /*测试 画IMAGELIST的矩形*/
                //if (e.Node.ImageIndex > 0)
                //    e.Graphics.DrawRectangle(new Pen(Color.Black, 1), imagebox);
            }
            #endregion
        }

        protected override void OnBeforeSelect(TreeViewCancelEventArgs e)
        {
            base.OnBeforeSelect(e);
            if (e.Node != null)
            {
                //禁止选中空白项
                if (e.Node.Text == "")
                {
                    //响应上下键
                    if (ArrowKeyUp)
                    {
                        if (e.Node.PrevNode != null && e.Node.PrevNode.Text != "")
                            this.SelectedNode = e.Node.PrevNode;
                    }

                    if (ArrowKeyDown)
                    {
                        if (e.Node.NextNode != null && e.Node.NextNode.Text != "")
                            this.SelectedNode = e.Node.NextNode;
                    }

                    e.Cancel = true;
                }
            }
        }

        /// <summary>
        /// 防止在选择设，treeNode闪屏
        /// </summary>
        protected override CreateParams CreateParams
        {
            get
            {
                CreateParams cp = base.CreateParams;
                if (!DesignMode)
                {
                    cp.ExStyle |= 0x02000000;// Turn on WS_EX_COMPOSITED
                }
                return cp;

            }
        }
    }
}

　　

　生成后拖动控件到界面中，实际效果如下