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

最进在使用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

 1 using System.Data;
 2 using System.Text;
 3 using System.Windows.Forms;
 4 namespace WindowsApplication14
 5 {
 6     public class ComboBoxTreeView : ComboBox
 7     {
 8         private const int WM_LBUTTONDOWN = 0x201, WM_LBUTTONDBLCLK = 0x203;
 9         ToolStripControlHost treeViewHost;
10         ToolStripDropDown dropDown;
11         public ComboBoxTreeView()
12         {
13             TreeView treeView = new TreeView();
14             treeView.AfterSelect+=new TreeViewEventHandler(treeView_AfterSelect);
15             treeView.BorderStyle = BorderStyle.None;
16            
17             treeViewHost = new ToolStripControlHost(treeView);
18             dropDown = new ToolStripDropDown();
19             dropDown.Width = this.Width;
20             dropDown.Items.Add(treeViewHost);
21         }
22         public void treeView_AfterSelect(object sender, TreeViewEventArgs e)
23         {
24             this.Text=TreeView.SelectedNode.Text;
25             dropDown.Close();
26         }
27         public TreeView TreeView
28         {
29             get { return treeViewHost.Control as TreeView; }
30         }
31         private void ShowDropDown()
32         {
33             if (dropDown != null)
34             {
35                treeViewHost.Size =new Size(DropDownWidth-2,DropDownHeight);       
36                dropDown.Show(this, 0, this.Height);
37             }
38         }
39         protected override void WndProc(ref Message m)
40         {
41             if (m.Msg == WM_LBUTTONDBLCLK || m.Msg == WM_LBUTTONDOWN)
42             {
43                 ShowDropDown();
44                 return;
45             }        
46             base.WndProc(ref m);
47         }
48         protected override void Dispose(bool disposing)
49         {
50             if (disposing)
51             {
52                 if (dropDown != null)
53                 {
54                     dropDown.Dispose();
55                     dropDown = null;
56                 }
57             }
58             base.Dispose(disposing);
59         }
60     }
61 
62 }
63 

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
    {
        ToolStripComboBoxTreeViewControl#region ToolStripComboBoxTreeViewControl
        internal class ToolStripComboBoxTreeViewControl  : ComboBox
        {
            private const int WM_LBUTTONDOWN = 0x201, WM_LBUTTONDBLCLK = 0x203;
            ToolStripControlHost treeViewHost;
            ToolStripDropDown dropDown;
            private ToolStripComboBoxTreeView owner;

            public ToolStripComboBoxTreeView Owner
            {
                get
                {
                    return owner;
                }
                set
                {
                    owner = value;
                }
            }
            public ToolStripComboBoxTreeViewControl()
            {
                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;
                if (Owner.DropDown != null)
                {
                    Owner.DropDown(this, e);
                }
                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);
            }
        }
        #endregion
        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#region 属性
        [Browsable(false), DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
        public ComboBox ComboBox
        {
            get
            {
                return (base.Control as ComboBox);
            }
        }
        [Browsable(true)]
        public TreeView TreeView
        {
            get
            {
                    ToolStripComboBoxTreeView.ToolStripComboBoxTreeViewControl control = 
                base.Control as ToolStripComboBoxTreeView.ToolStripComboBoxTreeViewControl;
                    return control.TreeView;
            }
        }
        [DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
        [Editor("System.Windows.Forms.Design.ListControlStringCollectionEditor, System.Design, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a", typeof(UITypeEditor))]
        [Browsable(true)]
        [EditorBrowsable(EditorBrowsableState.Always)] 
        [Localizable(true)]
        public AutoCompleteStringCollection AutoCompleteCustomSource
        {
            get
            {
                return this.ComboBox.AutoCompleteCustomSource;
            }
            set
            {
                this.ComboBox.AutoCompleteCustomSource = value;
            }
        }
        [Browsable(false)]
        [ DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
        public int SelectionLength
        {
            get
            {
                return this.ComboBox.SelectionLength;
            }
            set
            {
                this.ComboBox.SelectionLength = value;
            }
        }
        [Browsable(false)]
        [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
        public int SelectionStart
        {
            get
            {
                return this.ComboBox.SelectionStart;
            }
            set
            {
                this.ComboBox.SelectionStart = value;
            }
        }
        [DefaultValue(0)]
        [Localizable(true)]
        [Description("下拉框最大长度")]
        public int MaxLength
        {
            get
            {
                return this.ComboBox.MaxLength;
            }
            set
            {
                this.ComboBox.MaxLength = value;
            }
        }    
        [DefaultValue(1)]
        [RefreshProperties(RefreshProperties.Repaint)]
        public ComboBoxStyle DropDownStyle
        {
            get
            {
                return this.ComboBox.DropDownStyle;
            }
            set
            {
                this.ComboBox.DropDownStyle = value;
            }
        }
        [EditorBrowsable(EditorBrowsableState.Always)]
        [Browsable(true)]
        [DefaultValue(106)]
        public int DropDownHeight
        {
            get
            {
                return this.ComboBox.DropDownHeight;
            }
            set
            {
                this.ComboBox.DropDownHeight = value;
            }
        }
        public int DropDownWidth
        {
            get
            {
                return this.ComboBox.DropDownWidth;
            }
            set
            {
                this.ComboBox.DropDownWidth = value;
            }
        }
        #endregion
        方法#region 方法
        public void SelectAll()
        {
            ComboBox.SelectAll();
        }
        public void Select(int start, int length)
        {
            ComboBox.Select(start, length);
        }
        #endregion
        事件#region 事件
      
        public event EventHandler DropDown;
 
        #endregion
       
    }
}

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);
}