VS2005下ComboBoxTreeView(下拉列表框弹出树) 与ToolStripComboBoxTreeView(下拉列表框工具条弹出树)的实现

使用VS2005开发时,发现有很多新东西,比如,我们常用的ToolBar ,MainMenu,StatusBar,变成了功能强大,样式新颖的,ToolStrip,MenuStrip,StatusStrip,等.不过还是有些不足,比如,ComboBox 变化不大,下拉框里面只能是文本的,很不方便,我的想法是在下拉ComboBox时会出现TreeView 控件,这也是我今天要做的控件ComboBoxTreeView
开始写了一个,关键点是弹出TreeView 控件,但是把TreeView 做成一个窗体,弹出,还是有什么办法,一查VS2005有一个类窗体弹出类(很强大的对象)ToolStripDropDown, 在使用此类的时候需要传递一个ToolStripControlHost类型的对象,还有个问题就是,TreeView 弹出了,会在它的上方出现了一条小白条,这个问题很棘手,不过如果你懂Win32那就一切OK了,好,我们看看这个类吧．
一：ComboBoxTreeView

using System.Data;
using System.Text;
using System.Windows.Forms;
namespace WindowsApplication14
{
    public class ComboBoxTreeView : ComboBox
    {
        private const int WM_LBUTTONDOWN = 0x201, WM_LBUTTONDBLCLK = 0x203;
        ToolStripControlHost treeViewHost;
        ToolStripDropDown dropDown;
        public ComboBoxTreeView()
        {
            TreeView treeView = new TreeView();
            treeView.AfterSelect+=new TreeViewEventHandler(treeView_AfterSelect);
            treeView.BorderStyle = BorderStyle.None;
           
            treeViewHost = new ToolStripControlHost(treeView);
            dropDown = new ToolStripDropDown();
            dropDown.Width = this.Width;
            dropDown.Items.Add(treeViewHost);
        }
        public void treeView_AfterSelect(object sender, TreeViewEventArgs e)
        {
            this.Text=TreeView.SelectedNode.Text;
            dropDown.Close();
        }
        public TreeView TreeView
        {
            get { return treeViewHost.Control as TreeView; }
        }
        private void ShowDropDown()
        {
            if (dropDown != null)
            {
               treeViewHost.Size =new Size(DropDownWidth-2,DropDownHeight);       
               dropDown.Show(this, 0, this.Height);
            }
        }
        protected override void WndProc(ref Message m)
        {
            if (m.Msg == WM_LBUTTONDBLCLK || m.Msg == WM_LBUTTONDOWN)
            {
                ShowDropDown();
                return;
            }        
            base.WndProc(ref m);
        }
        protected override void Dispose(bool disposing)
        {
            if (disposing)
            {
                if (dropDown != null)
                {
                    dropDown.Dispose();
                    dropDown = null;
                }
            }
            base.Dispose(disposing);
        }
    }

}

附图:

二：
ToolStrip
工具条中可以插入文本，下拉框，等，如果要插入下拉树的列表框但不可以直接插入ComboBoxTreeView，必须继承上面提到的ToolStripControlHost类，

using System;
using System.Windows;
using System.Windows.Forms;
using System.ComponentModel;
using System.Drawing;
using System.Drawing.Design;
using System.Windows.Forms.Design;

namespace WindowsApplication14
{
    [DefaultProperty("Items")]
    [ToolStripItemDesignerAvailability(ToolStripItemDesignerAvailability.ContextMenuStrip | (ToolStripItemDesignerAvailability.MenuStrip | ToolStripItemDesignerAvailability.ToolStrip))]
    public class ToolStripComboBoxTreeView : ToolStripControlHost
    {
        ToolStripComboBoxTreeViewControlToolStripComboBoxTreeViewControlToolStripComboBoxTreeViewControl
        public ToolStripComboBoxTreeView()
            : base(ToolStripComboBoxTreeView.CreateControlInstance())
        {
            ToolStripComboBoxTreeView.ToolStripComboBoxTreeViewControl control = 
                base.Control as ToolStripComboBoxTreeView.ToolStripComboBoxTreeViewControl;
                control.Owner = this;
                

        }
        private static Control CreateControlInstance()
        {
            ComboBox comboBox = new ToolStripComboBoxTreeViewControl();
            return comboBox;
        }
        属性属性属性
        方法方法方法
        事件事件事件
       
    }
}

附图：

客户端调用方法：
public static void Main(){
   toolStripComboBoxTreeView1.TreeView.ImageList = this.imageList1;
            TreeNode root = new TreeNode("根节点",1,2);
            root.Nodes.Add("节点1");
            root.Nodes.Add("节点2");
            root.Nodes.Add("节点3");
            root.Nodes.Add("节点4");
            root.Nodes.Add("节点5");
            root.Nodes.Add("节点6");
            toolStripComboBoxTreeView1.TreeView.Nodes.Add(root);