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 = 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