C#重写treeView控件

1.先准备两张图片downdrop.png、downdrop_open.png放在项目Resources里

2.新建用户控件BaseTreeView控件

3.重写控件继承TreeView，记得删除AutoScaleMode这一行，否则会报错

public partial class BaseTreeView : TreeView
{//这个属性貌似不起作用，还是得配置BackColor不知道是咋回事private Color nodeNormalBackColor = Color.FromArgb(10, 52, 112);public Color NodeNormalBackColor{get{return nodeNormalBackColor;}set{nodeNormalBackColor = value;}}private Color nodeSelectBackColor = Color.FromArgb(15, 92, 164);public Color NodeSelectBackColor{get{return nodeSelectBackColor;}set{nodeSelectBackColor = value;}}private Color nodeHoverBackColor = Color.FromArgb(103, 161, 207);public Color NodeHoverBackColor{get{return nodeHoverBackColor;}set{nodeHoverBackColor = value;}}private Color nodeTestColor = Color.FromArgb(203, 239, 255);public Color NodeTestColor{get{return nodeTestColor;}set{nodeTestColor = value;}}public BaseTreeView(){InitializeComponent();this.DrawMode = TreeViewDrawMode.OwnerDrawAll;this.FullRowSelect = true;this.ItemHeight = 46;this.HotTracking = true;this.ShowLines = true;}protected override void OnDrawNode(DrawTreeNodeEventArgs e){base.OnDrawNode(e);//节点背景绘制if (e.Node.IsSelected){//e.Graphics.DrawImage(Properties.Resources.tree_bg, e.Bounds);e.Graphics.FillRectangle(new SolidBrush(nodeSelectBackColor), e.Bounds);}else if ((e.State & TreeNodeStates.Hot) != 0)//|| currentMouseMoveNode == e.Node){//e.Graphics.DrawImage(Properties.Resources.tree_bg, e.Bounds);e.Graphics.FillRectangle(new SolidBrush(nodeHoverBackColor), e.Bounds);}else if (e.Node.BackColor != null) {//这个是用于特殊单独需要在代码里设置结点背景颜色时使用Color color = e.Node.BackColor; // 获取背景色的全部分量e.Graphics.FillRectangle(new SolidBrush(color), e.Bounds);}else{e.Graphics.FillRectangle(new SolidBrush(nodeNormalBackColor), e.Bounds);}//节点头图标绘制if (e.Node.IsExpanded){e.Graphics.DrawImage(Resources.downdrop_open, e.Node.Bounds.X - 18, e.Node.Bounds.Y + 10);}else if (e.Node.IsExpanded == false && e.Node.Nodes.Count > 0){e.Graphics.DrawImage(Resources.downdrop, e.Node.Bounds.X - 18, e.Node.Bounds.Y + 10);}//文本绘制using (Font foreFont = new Font(this.Font, FontStyle.Regular))using (Brush drawTextBrush = new SolidBrush(nodeTestColor)){e.Graphics.DrawString(e.Node.Text, foreFont, drawTextBrush, e.Node.Bounds.Left + 15, e.Node.Bounds.Top + 5);}}protected override void OnMouseClick(MouseEventArgs e){base.OnMouseClick(e);TreeNode tn = this.GetNodeAt(e.Location);this.SelectedNode = tn;}TreeNode currentNode = null;protected override void OnMouseMove(MouseEventArgs e){base.OnMouseMove(e);TreeNode tn = this.GetNodeAt(e.Location);Graphics g = this.CreateGraphics();if (currentNode != tn){//绘制当前节点的hover背景if (tn != null)OnDrawNode(new DrawTreeNodeEventArgs(g, tn, new Rectangle(0, tn.Bounds.Y, this.Width, tn.Bounds.Height), TreeNodeStates.Hot));//取消之前hover的节点背景if (currentNode != null)OnDrawNode(new DrawTreeNodeEventArgs(g, currentNode, new Rectangle(0, currentNode.Bounds.Y, this.Width, currentNode.Bounds.Height), TreeNodeStates.Default));}currentNode = tn;g.Dispose();}protected override void OnMouseLeave(EventArgs e){base.OnMouseLeave(e);//移出控件时取消Hover背景if (currentNode != null){Graphics g = this.CreateGraphics();OnDrawNode(new DrawTreeNodeEventArgs(g, currentNode, new Rectangle(0, currentNode.Bounds.Y, this.Width, currentNode.Bounds.Height), TreeNodeStates.Default));}}/// <summary>/// 防止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;}}
}

4.重新生成程序，在工具箱中就会出现BaseTreeView控件，拉到界面中即可使用

5.在使用界面中为TreeView添加几个数据测试

//创建父节点
TreeNode treeNode = baseTreeView1.Nodes.Add("组织结构");//创建子节点
TreeNode treeNode_1 = new TreeNode("C");
TreeNode treeNode_2 = new TreeNode("C++");
TreeNode treeNode_3 = new TreeNode("C#");//给父节点添加子节点
treeNode.Nodes.Add(treeNode_1);
treeNode.Nodes.Add(treeNode_2);
treeNode.Nodes.Add(treeNode_3);

将文字设置大一点，背景颜色设置的深一点更好看