具有自动完成功能的ComboBox

根据你输入的内容自动过滤出匹配的列表项，并实时显示出来，和IE地址栏类似。
程序很简单，只是很长事时间没更新blog了，用这篇小文章来更新一下。

程序原理是这样的：组件继承之combobox，并且拥有一个listbox成员，当组件的text改变时，就从combobox中过滤出匹配的列表项，并且把这些列表项加入到listbox中显示出来。

using System;

using System.Collections;

 

using System.ComponentModel;

 

using System.Drawing;

 

using System.Data;

 

using System.Windows.Forms;

 

 

 

namespace XPangLib

 

{

 

     /// <summary>

 

     /// AutoComboBox 的摘要说明。

 

     /// </summary>

 

     public class AutoComboBox : System.Windows.Forms.ComboBox

 

     {

 

 

 

          private System.Windows.Forms.ListBox lbMain;

 

         /// <summary>

 

         /// 必需的设计器变量。

 

         /// </summary>

 

          private System.ComponentModel.Container components = null;

 

 

 

         public AutoComboBox()

 

         {

 

              // 该调用是 Windows.Forms 窗体设计器所必需的。

 

              InitializeComponent();

 

 

 

              lbMain = new ListBox() ;

 

              lbMain.Click+=new EventHandler(lbMain_Click);

 

              lbMain.KeyDown+=new KeyEventHandler(lbMain_KeyDown);

 

              lbMain.Visible = false ;         

 

         }

 

         /// <summary>

 

         /// 得到匹配给定字符串的列表

 

         /// </summary>

 

          private ArrayList GetFillList(string strValue)

 

         {

 

              ArrayList alReturn = new ArrayList() ;

 

              int iCount = this.Items.Count ;

 

              int iLen = strValue.Length ;

 

 

 

              for(int i = 0 ;i < iCount ;i++)

 

              {

 

                   string strSelItem = this.Items[i].ToString() ;

 

 

 

                   if (strSelItem.Length < iLen)

 

                        continue ;

 

 

 

                   if (strSelItem.Substring(0,iLen) == strValue)

 

                   alReturn.Add(strSelItem) ;

 

              }

 

             

 

              return alReturn ;

 

         }

 

         /// <summary>

 

         /// 清理所有正在使用的资源。

 

         /// </summary>

 

          protected override void Dispose( bool disposing )

 

         {

 

              if( disposing )

 

              {

 

                   if( components != null )

 

                        components.Dispose();

 

              }

 

              base.Dispose( disposing );

 

         }

 

 

 

          #region 组件设计器生成的代码

 

         /// <summary>

 

         /// 设计器支持所需的方法 - 不要使用代码编辑器

 

         /// 修改此方法的内容。

 

         /// </summary>

 

          private void InitializeComponent()

 

         {//

 

              // AutoComboBox

 

              //

 

              this.Sorted = true;

 

              this.KeyDown += new System.Windows.Forms.KeyEventHandler(this.AutoComboBox_KeyDown);

 

              this.DropDown += new System.EventHandler(this.AutoComboBox_DropDown);

 

              this.TextChanged += new System.EventHandler(this.AutoComboBox_TextChanged);

 

              this.SelectedIndexChanged += new System.EventHandler(this.AutoComboBox_SelectedIndexChanged);

 

              this.Leave += new System.EventHandler(this.AutoComboBox_Leave);

 

 

 

         }

 

          #endregion

 

 

 

          protected override void OnPaint(PaintEventArgs pe)

 

         {

 

              // TODO: 在此添加自定义绘画代码

 

 

 

              // 调用基类 OnPaint

 

              base.OnPaint(pe);

 

         }

 

          private void lbMain_Click(object sender, System.EventArgs e)

 

         {

 

              if (lbMain.SelectedItems.Count == 0)

 

                   return ;

 

              string strSel = lbMain.SelectedItem.ToString() ;

 

              this.Text = strSel ;

 

              int iSel = this.FindStringExact(Text) ;

 

              if (iSel != -1)

 

                   this.SelectedIndex = iSel ;

 

              lbMain.Visible = false ;

 

         }

 

          private void AutoComboBox_TextChanged(object sender, System.EventArgs e)

 

         {

 

              if (Text == "")

 

              {

 

                   lbMain.Visible = false ;

 

                   return ;

 

              }

 

              if (!this.Parent.Controls.Contains(lbMain))

 

              {

 

                   lbMain.Width = this.Width ;

 

                   lbMain.Height = 100 ;

 

                   lbMain.Parent = this.Parent ;

 

                   lbMain.Top = this.Top + this.Height + 1 ;

 

                   lbMain.Left = this.Left ;

 

                   this.Parent.Controls.Add(lbMain);

 

                   lbMain.BringToFront() ;

 

              }

 

              ArrayList alFill  = GetFillList(Text) ;

 

              lbMain.Items.Clear() ;

 

              lbMain.Items.AddRange(alFill.ToArray()) ;

 

              if (lbMain.Items.Count > 0)

 

                   lbMain.SelectedIndex = 0 ;

 

              if (!lbMain.Visible)

 

                   lbMain.Visible = true ;

 

         }

 

 

 

          private void AutoComboBox_Leave(object sender, System.EventArgs e)

 

         {

 

              if (!lbMain.Focused)

 

                   lbMain.Visible = false ;

 

         }

 

 

 

          private void AutoComboBox_DropDown(object sender, System.EventArgs e)

 

         {

 

              lbMain.Visible = false ;

 

         }

 

 

 

          private void AutoComboBox_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)

 

         {

 

              if (lbMain.Visible)

 

              {

 

                   if (e.KeyCode == Keys.Up||e.KeyCode == Keys.Down||e.KeyCode == Keys.Left||

 

                        e.KeyCode == Keys.Right||e.KeyCode == Keys.PageDown||e.KeyCode == Keys.PageUp)

 

                   {

 

                        lbMain_KeyDown(lbMain,e) ;

 

                        e.Handled = true ;                

 

                   }

 

                   else if (e.KeyCode == Keys.Enter)

 

                   {

 

                        lbMain_Click(lbMain,e) ;

 

                        e.Handled = true ;  

 

                   }

 

              }

 

         }

 

          private void lbMain_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)

 

         {

 

        

 

              if (e.KeyCode == Keys.Up||e.KeyCode == Keys.Left||e.KeyCode == Keys.PageUp)

 

              {

 

                   if (lbMain.SelectedIndex > 0)

 

                        lbMain.SelectedIndex = lbMain.SelectedIndex - 1 ;

 

              }

 

              else if (e.KeyCode == Keys.Down||e.KeyCode == Keys.Right||e.KeyCode == Keys.PageDown)

 

              {

 

                   if (lbMain.SelectedIndex < lbMain.Items.Count - 1)

 

                        lbMain.SelectedIndex = lbMain.SelectedIndex + 1 ;

 

              }

 

         }

 

 

 

          private void AutoComboBox_SelectedIndexChanged(object sender, System.EventArgs e)

 

         {

 

              lbMain.Visible = false ;

 

         }

 

     }//end class

 

}//end namespace

在GetFillList()函数中把
if (strSelItem.Substring(0,iLen) == strValue)
改成
if (strSelItem.Substring(0,iLen).ToLower() == strValue.ToLower())
可以进行忽略大小写的模糊匹配。