AutoCompleteTextBox源代码

//  ********************************************************
//  自动完成控件
//  Designed by Faib Studio.
//  Copyright 2007
//  Email [email protected] or QQ 55570729
//  ********************************************************

using  System;
using  System.Web.UI;
using  System.Web.UI.Design;
using  System.Web.UI.WebControls;
using  System.ComponentModel;
using  System.Collections.Specialized;
using  System.Drawing;
using  System.Drawing.Design;

namespace  FaibClass.WebControls
{
    [DefaultProperty("Text")]
    [ParseChildren(true, "Items")]
    [DefaultEvent("Changed")]
    [ToolboxData("<{0}:AutoCompleteTextBox runat=server></{0}:AutoCompleteTextBox>")]
    public class AutoCompleteTextBox : BaseTextBox, IPostBackDataHandler, IPostBackEventHandler
    {
        [Description("列表项改变时。")]
        public event EventHandler Changed;

        私有变量#region 私有变量
        private ListItemCollection m_lics;
        private int m_Rows = 8;
        private bool m_SendKeyTab = false;
        private bool m_MatchAnywhere = true;
        private bool m_ListAllItemOnFocus = true;
        private ListItem m_SelectedItem = null;
        private int m_SelectedIndex = -1;
        #endregion

        public AutoCompleteTextBox()
        {
            m_lics = new ListItemCollection();
        }

        属性#region 属性
        [Category("Appearance")]
        [Description("文本值。")]
        [PersistenceMode(PersistenceMode.Attribute)]
        public override string Text
        {
            get{return base.Text;}
            set{base.Text = value;}
        }

        [Category("Data")]
        [Description("列表中项的集合。")]
        [DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
        [NotifyParentProperty(true)]
        [PersistenceMode(PersistenceMode.InnerDefaultProperty)]
        public ListItemCollection Items
        {
            get{return m_lics;}
        }

        [Category("Appearance")]
        [Description("列表显示的行数。")]
        [DefaultValue(8)]
        public new int Rows
        {
            get{return m_Rows;}
            set{m_Rows = value;}
        }

        [Category("Behavior")]
        [Description("按回车选择时是否发移到下一控件。")]
        [DefaultValue(false)]
        public bool SendKeyTab
        {
            get{return m_SendKeyTab;}
            set{m_SendKeyTab = value;}
        }

        [Category("Behavior")]
        [Description("是否匹配任意位置的字符串。")]
        [DefaultValue(true)]
        public bool MatchAnywhere
        {
            get{return m_MatchAnywhere;}
            set{m_MatchAnywhere = value;}
        }
        
        [Category("Behavior")]
        [Description("是否在获得焦点时列出所有项。")]
        [DefaultValue(true)]
        public bool ListAllItemOnFocus
        {
            get{return m_ListAllItemOnFocus;}
            set{m_ListAllItemOnFocus = value;}
        }

        [Browsable(false)]
        [Description("返回被选中项。")]
        public ListItem SelectedItem
        {
            get{return m_SelectedItem;}
        }

        [Browsable(false)]
        [Description("返回被选中项的索引。")]
        [DefaultValue(-1)]
        public int SelectedIndex
        {
            get{return m_SelectedIndex;}
            set{
                m_SelectedIndex = value;
                m_SelectedItem = m_lics[m_SelectedIndex];
                this.Text = m_SelectedItem.Text;
            }
        }

        internal new TextBoxMode TextMode
        {
            get{return TextBoxMode.SingleLine;}
        }

        internal new bool Wrap
        {
            get{return false;}
        }

        internal new int MaxLength
        {
            get{return 0;}
        }

        internal new int Columns
        {
            get{return 0;}
        }
        #endregion

        公有方法#region 公有方法
        protected override void OnInit(EventArgs e)
        {
            if (Page != null)
            {
                //将控件注册为需要回发处理的控件
                Page.RegisterRequiresPostBack(this);
            }
            base.OnInit (e);
        }

        protected override void OnPreRender(EventArgs e)
        {
            base.OnPreRender (e);
            if (Page != null)
            {
                //注册隐藏字段，用于保存客户端选择的索引及对Items的修改
                Page.RegisterHiddenField("__" + this.ClientID + "_State__", m_SelectedIndex.ToString() + "※");
            }
        }

        protected override void OnLoad(EventArgs e)
        {
            //注册一个js文件到缓存中
            Util.RegisterCacheFile(Page, "AutoCompleteTextBox", "autocompleteTextbox.fbs.ashx", "Resource.AutoCompleteTextBox.js");
            //输出控件初始化脚本
            Util.RegisterStartupScript(Page, "AutoCompleteTextBox_" + this.ClientID, "\n<script>\nif(document.getElementById(\"" + this.ClientID + "\")){AutoCompleteBox_Init(document.getElementById(\"" + this.ClientID + "\"));}\n</script>");
            //添加属性
            Attributes.Add("rows", m_Rows.ToString());
            if(AutoPostBack)Attributes.Add("autopostback", "1");
            if(m_MatchAnywhere)Attributes.Add("matchanywhere", "1");
            if(m_ListAllItemOnFocus)Attributes.Add("listallitemonfocus", "1");
            if(m_SendKeyTab)Attributes.Add("sendkeytab", "1");

            base.OnLoad (e);
        }

        protected override void Render(HtmlTextWriter output)
        {
            base.Render (output);
            if(IsDesignMode)return;
            //输出Items中的每一项生成fsc:ListItem标签
            output.Write("<?XML:NAMESPACE PREFIX=\"fsc\" />");
            output.AddAttribute("id", this.ClientID + "_items");
            output.RenderBeginTag("fsc:AutoCompleteTextBox");
            foreach(ListItem lt in m_lics)
            {
                output.WriteBeginTag("fsc:ListItem");
                output.WriteAttribute("value", lt.Value);
                output.WriteAttribute("text", lt.Text);
                output.WriteLine(" />");
            }
            output.RenderEndTag();
        }

        [DescriptionAttribute("引发 PageIndexChanged 事件。")]
        protected virtual void OnChanged()
        {
            if(Changed != null) 
            {
                Changed(this, new EventArgs());
            }
        }

        protected override void LoadViewState(object savedState)
        {
            base.LoadViewState (savedState);
            //将Items保存到ViewState，由于ListItem不支持序列化，所以需要使用自定义类来进行保存
            if (ViewState["Items"] != null)
                m_lics = Util.LoadListItemFromViewState(ViewState["Items"]);
        }

        protected override object SaveViewState()
        {
            //从ViewState中读取Items
            ViewState["Items"] = Util.SaveListItemToViewState(m_lics);
            return base.SaveViewState ();
        }
        #endregion

        接口#region 接口
        void IPostBackDataHandler.RaisePostDataChangedEvent()
        {
        }

        void IPostBackEventHandler.RaisePostBackEvent(string eventArgument)
        {
            //触发事件
            if(eventArgument == "")
                OnChanged();
        }

        bool IPostBackDataHandler.LoadPostData(String postDataKey, NameValueCollection values) 
        {
            //处理回发数据
            string value = values["__" + this.ClientID + "_State__"];
            if (value != null)
            {
                string[] data = value.Split('※');//客户端Items的修改，使用saveState后生成的数据
                if(data[1] != "")
                {
                    m_lics.Clear();
                    for(int i = 1; i < data.Length; i++)
                    {
                        string[] da1 = data[i].Split('□');
                        m_lics.Add(new ListItem(da1[0], da1[1]));
                    }
                    SaveViewState();
                }
                if(values[this.ClientID].Length == 0)
                {
                    m_SelectedIndex = -1;
                    m_SelectedItem = null;
                }
                else
                {
                    if(data[0].CompareTo("-1") != 0)//选定项
                    {
                        try
                        {
                            m_SelectedIndex = int.Parse(data[0]);
                            m_SelectedItem = this.Items[m_SelectedIndex];
                        }
                        catch
                        {
                            throw;
                        }
                    }
                }
            }
            this.Text = values[this.ClientID];
            return false;
        }
        #endregion
    }
}

此控件继承自BaseTextBox类，BaseTextBox是一个简单的类，目前只实现了一个属性：

         protected   internal   virtual   bool  IsDesignMode
         {
            get { return (Site != null) ? Site.DesignMode : false; }
        }

Javascript源代码见 http://www.cnblogs.com/faib/archive/2007/05/10/741875.html