带复选框的TreeView

项目中多处用到TreeView，每一个树都要全选、取消全选、层级联动、屏蔽双击复选框，于是很有必要封装一个CheckTreeView，步骤如下：

1. 在项目中右键->添加->新建项，选择Windows Forms下的用户控件，名称改为CheckTreeView.cs
2. 拖入一个TreeView，CheckBoxes属性改为True，Dock属性改为Fill
3. 拖入一个contextMenuStrip，添加子项“全选”和“全不选”，并双击子项生成事件处理函数
4. 将treeView1的ContextMenuStrip属性改为contextMenuStrip1
5. 编写如下代码，然后在CheckTreeView.Designer.cs中，将treeView1的类型改为TreeViewEnhanced

using System;
using System.Collections.Generic;
using System.Windows.Forms;

namespace MyControls
{
    public partial class CheckTreeView : UserControl
    {
        bool _isEnglish = false;
        public CheckTreeView()
        {
            InitializeComponent();
            treeView1.CheckBoxes = true;
        }

        public bool IsEnglish
        {
            get
            {
                return _isEnglish;
            }
            set
            {
                _isEnglish = value;
                if (_isEnglish)
                {
                    contextMenuStrip1.Items[0].Text = "CheckAll";
                    contextMenuStrip1.Items[1].Text = "CheckNone";
                }
                else
                {
                    contextMenuStrip1.Items[0].Text = "全选";
                    contextMenuStrip1.Items[1].Text = "全不选";
                }
            }
        }

        public TreeView TreeView { get { return treeView1; } }

        /// <summary>
        /// 全选
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void menu_CheckNone_Click(object sender, EventArgs e)
        {
            foreach (TreeNode node in treeView1.Nodes)
            {
                node.Checked = false;            
                setChildNodeCheckedState(node, false);
            }
        }

        /// <summary>
        /// 全部不选
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void menu_CheckAll_Click(object sender, EventArgs e)
        {
            foreach (TreeNode node in treeView1.Nodes)
            {
                node.Checked = true;             
                setChildNodeCheckedState(node, true);
            }
        }

        private void treeView1_AfterCheck(object sender, TreeViewEventArgs e)
        {
            if (e.Action == TreeViewAction.ByMouse)
            {
                if (e.Node.Checked)
                {
                    setChildNodeCheckedState(e.Node, true);
                    if (e.Node.Parent != null) SetParentState(e.Node);
                }
                else
                {
                    setChildNodeCheckedState(e.Node, false);
                    if (e.Node.Parent != null) SetParentState(e.Node);
                }
            }
        }

        /// <summary>
        /// 选中节点时，若兄弟节点都选中则选中上级；取消选择时，取消上级选择
        /// </summary>
        /// <param name="currNode">当前节点</param>
        private void SetParentState(TreeNode currNode)
        {
            TreeNode parentNode = currNode.Parent;
            bool brotherChecked = true;
            foreach (TreeNode node in parentNode.Nodes)
            {
                if (!node.Checked)
                {
                    brotherChecked = false;
                    break;
                }
            }
            parentNode.Checked = brotherChecked;
            if (parentNode.Parent != null) SetParentState(parentNode);
        }
                
        /// <summary>
        /// 选中节点之后，选中节点的所有子节点；取消选择时，取消所有子节点选择
        /// </summary>
        /// <param name="currNode">当前节点</param>
        /// <param name="state">是否选中</param>
        private void setChildNodeCheckedState(TreeNode currNode, bool state)
        {
            TreeNodeCollection nodes = currNode.Nodes;
            if (nodes.Count > 0)
            {
                foreach (TreeNode tn in nodes)
                {
                    tn.Checked = state;                  
                    setChildNodeCheckedState(tn, state);
                }
            }
        }

        public List<string> GetAllCheckedNodeNames()
        {
            var names = new List<string>();
            foreach (TreeNode node in treeView1.Nodes)
            {
                if (node.Checked && !names.Contains(node.Name)) names.Add(node.Name);
                GetCheckedChildrenName(node, names);
            }
            return names;
        }

        private void GetCheckedChildrenName(TreeNode currNode, List<string> names)
        {
            foreach (TreeNode node in currNode.Nodes)
            {
                if (node.Checked && !names.Contains(node.Name)) names.Add(node.Name);
                GetCheckedChildrenName(node, names);
            }
        }      
    }

    public class TreeViewEnhanced : TreeView
    {
        protected override void WndProc(ref Message m)
        {
            if (m.Msg == 0x203) { m.Result = IntPtr.Zero; }//取消双击事件
            else base.WndProc(ref m);            
        }
    }
}