ASP.NET: Custom AutoCompleteTextBox WebControl [With Source Code]

这是一个Teddy最近封装的AutoCompleteTextBox。我们知道，ASP.NET本身的TextBox也是支持一定的AutoComplete功能的，但是那是依赖浏览器实现的，并不能指定自定义的AutoComplete候选项。本文列举的AutoCompleteTextBox则弥补了这个缺憾。只需设置AutoCompleteTextBox.AutoCompleteData属性，传递一个string[]，就能使TextBox支持自定义候选项了。

AutoComplete逻辑

如果没有匹配当前输入的候选项，则同一般的TextBox；
如果只有一个候选项与当前输入匹配，则自动完成；
如果有超过一个候选项与当前输入匹配，则在textbox中自动完成第一个候选项，并弹出包含所有候选项的弹出框。

实现源码

源码是在VS2005编译的，不过实际上几乎没有使用依赖2.0的语法，在vs2003下经极少修改就同样能编译的。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Text;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;

namespace Ilungasoft.Framework.Web.UI.WebControls
{
    [ToolboxData("<{0}:AutoCompleteTextBox runat=server></{0}:AutoCompleteTextBox>")]
    public class AutoCompleteTextBox : WebControl
    {
        Private Members#region Private Members

        private TextBox textBox = new TextBox();
        private HtmlGenericControl autoCompleteFrame = new HtmlGenericControl();

        private string ToJsStringArray(params string[] strs)
        {
            if (strs != null && strs.Length > 0)
            {
                StringBuilder sb = new StringBuilder();
                sb.Append(" new Array(");

                foreach (string str in strs)
                {
                    sb.Append(string.Format("'{0}', ", str.Replace("'", "\\'")));
                }

                return sb.ToString().TrimEnd(',', ' ') + ");";
            }
            else
            {
                return " new Array;";
            }
        }

        private string MakeUniqueID(string id)
        {
            if (id != null && id.Trim().Length > 0)
            {
                return string.Concat(this.UniqueID.Replace("$", "_"), "_", id);
            }
            else
            {
                return this.UniqueID.Replace("$", "_");
            }
        }

        #endregion

        Properties#region Properties

        [Bindable(true)]
        [Category("Appearance")]
        [DefaultValue("")]
        [Localizable(true)]
        public string Text
        {
            get
            {
                if (Page.IsPostBack)
                {
                    textBox.Text = Page.Request.Form[MakeUniqueID("textBox")];
                }
                return textBox.Text;
            }
            set
            {
                textBox.Text = value;
            }
        }

        [Bindable(true)]
        [Category("Behavior")]
        [DefaultValue("")]
        [Localizable(true)]
        public int MaxLength
        {
            get
            {
                return textBox.MaxLength;
            }
            set
            {
                textBox.MaxLength = value;
            }
        }

        [Bindable(true)]
        [Category("Behavior")]
        [DefaultValue(false)]
        [Localizable(true)]
        public bool ReadOnly
        {
            get
            {
                return textBox.ReadOnly;
            }
            set
            {
                textBox.ReadOnly = value;
            }
        }

        public string[] AutoCompleteData
        {
            get
            {
                string[] s = (string[])ViewState["AutoCompleteData"];
                return ((s == null) ? null : s);
            }
            set
            {
                ViewState["AutoCompleteData"] = value;
            }
        }

        #endregion

        Overriden Members#region Overriden Members

        protected override void CreateChildControls()
        {
            create textBox#region create textBox

            textBox.ID = MakeUniqueID("textBox");
            textBox.AutoCompleteType = AutoCompleteType.Disabled;
            textBox.Attributes.Add("onkeypress", string.Format("return __DoAutoComplete(event, '{0}')", MakeUniqueID(null)));
            textBox.Attributes.Add("onblur", string.Format("if (!document.show_{0}) document.getElementById('{1}').style.display = 'none';", MakeUniqueID(null), MakeUniqueID("autoCompleteFrame")));
            textBox.Width = Width;

            #endregion

            create autoCompleteFrame#region create autoCompleteFrame

            autoCompleteFrame.TagName = "iframe";
            autoCompleteFrame.ID = MakeUniqueID("autoCompleteFrame");
            autoCompleteFrame.Attributes.Add("style", "display:none; position: absolute; border: ridge 1px");
            autoCompleteFrame.Attributes.Add("frameborder", "0");
            autoCompleteFrame.Attributes.Add("marginheight", "0");
            autoCompleteFrame.Attributes.Add("marginwidth", "2");
            autoCompleteFrame.Attributes.Add("scrolling", "auto");
            autoCompleteFrame.Attributes.Add("width", Width.ToString());
            autoCompleteFrame.Attributes.Add("height", "100px");
            autoCompleteFrame.Attributes.Add("src", "javascript:''");
            autoCompleteFrame.Attributes.Add("onmouseover", string.Format("document.show_{0} = true;", MakeUniqueID(null)));
            autoCompleteFrame.Attributes.Add("onmouseout", string.Format("document.show_{0} = false;", MakeUniqueID(null)));

            #endregion
        }

        protected override void OnPreRender(EventArgs e)
        {
            Register Client Script Block#region Register Client Script Block

            if (!Page.ClientScript.IsClientScriptBlockRegistered("__DoAutoComplete"))
            {
                string script = string.Concat(
                    "<script language=\"javascript\" type=\"text/javascript\">\r\n",
                    "    var isOpera = navigator.userAgent.indexOf('Opera') > -1;\r\n",
                    "    var isIE = navigator.userAgent.indexOf('MSIE') > 1 && !isOpera;\r\n",
                    "    var isMoz = navigator.userAgent.indexOf('Mozilla/5.') == 0 && !isOpera;\r\n",
                    "\r\n",
                    "    function textboxSelect (oTextbox, iStart, iEnd)\r\n",
                    "    {\r\n",
                    "       switch(arguments.length) {\r\n",
                    "           case 1:\r\n",
                    "               oTextbox.select();\r\n",
                    "               break;\r\n",
                    "\r\n",
                    "           case 2:\r\n",
                    "               iEnd = oTextbox.value.length;\r\n",
                    "               /* falls through */\r\n",
                    "               \r\n",
                    "           case 3:          \r\n",
                    "               if (isIE) {\r\n",
                    "                   var oRange = oTextbox.createTextRange();\r\n",
                    "                   oRange.moveStart(\"character\", iStart);\r\n",
                    "                   oRange.moveEnd(\"character\", -oTextbox.value.length + iEnd);      \r\n",
                    "                   oRange.select();                                              \r\n",
                    "               } else if (isMoz){\r\n",
                    "                   oTextbox.setSelectionRange(iStart, iEnd);\r\n",
                    "               }                    \r\n",
                    "       }\r\n",
                    "\r\n",
                    "       oTextbox.focus();\r\n",
                    "    }\r\n",
                    "\r\n",
                    "    function textboxReplaceSelect (oTextbox, sText)\r\n",
                    "    {\r\n",
                    "       if (isIE) {\r\n",
                    "           var oRange = document.selection.createRange();\r\n",
                    "           oRange.text = sText;\r\n",
                    "           oRange.collapse(true);\r\n",
                    "           oRange.select();                                \r\n",
                    "       } else if (isMoz) {\r\n",
                    "           var iStart = oTextbox.selectionStart;\r\n",
                    "           oTextbox.value = oTextbox.value.substring(0, iStart) + sText + oTextbox.value.substring(oTextbox.selectionEnd, oTextbox.value.length);\r\n",
                    "           oTextbox.setSelectionRange(iStart + sText.length, iStart + sText.length);\r\n",
                    "       }\r\n",
                    "\r\n",
                    "       oTextbox.focus();\r\n",
                    "    }\r\n",
                    "\r\n",
                    "    function autocompleteMatch (sText, arrValues)\r\n",
                    "    {\r\n",
                    "       var retMatches = \"\"; \r\n",
                    "       \r\n",
                    "       for (var i=0; i < arrValues.length; i++)\r\n",
                    "       {\r\n",
                    "           if (arrValues[i].indexOf(sText) == 0)\r\n",
                    "           {\r\n",
                    "               retMatches += arrValues[i] + ',';\r\n",
                    "           }\r\n",
                    "       }\r\n",
                    "      \r\n",
                    "      if (retMatches.length > 0)\r\n",
                    "      {\r\n",
                    "          retMatches = retMatches.substr(0, retMatches.length - 1);\r\n",
                    "      } \r\n",
                    "\r\n",
                    "       return retMatches;\r\n",
                    "    }\r\n",
                    "\r\n",
                    "    function __DoAutoComplete(oEvent, id)\r\n",
                    "    {\r\n",
                    "        var oTextbox = document.getElementById(id + '_textBox');\r\n",
                    "        var frame = document.getElementById(id + '_autoCompleteFrame');\r\n",
                    "        var arrValues =  document[id + '_data'];\r\n",
                    "       \r\n",
                    "        switch (oEvent.keyCode) \r\n",
                    "        {\r\n",
                    "            case 38: //up arrow  \r\n",
                    "            case 40: //down arrow\r\n",
                    "            case 37: //left arrow\r\n",
                    "            case 39: //right arrow\r\n",
                    "            case 33: //page up  \r\n",
                    "            case 34: //page down  \r\n",
                    "            case 36: //home  \r\n",
                    "            case 35: //end                  \r\n",
                    "            case 13: //enter  \r\n",
                    "            case 9: //tab  \r\n",
                    "            case 27: //esc  \r\n",
                    "            case 16: //shift  \r\n",
                    "            case 17: //ctrl  \r\n",
                    "            case 18: //alt  \r\n",
                    "            case 20: //caps lock\r\n",
                    "            case 8: //backspace  \r\n",
                    "            case 46: //delete\r\n",
                    "                return true;\r\n",
                    "                break;\r\n",
                    "                \r\n",
                    "            default:\r\n",
                    "                textboxReplaceSelect(oTextbox, String.fromCharCode(isIE ? oEvent.keyCode : oEvent.charCode));\r\n",
                    "                var iLen = oTextbox.value.length;\r\n",
                    "\r\n",
                    "                var sMatches = autocompleteMatch(oTextbox.value, arrValues);\r\n",
                    "\r\n",
                    "                if (sMatches.length > 0)\r\n",
                    "                {\r\n",
                    "                   var arrMatches = sMatches.split(',');\r\n",
                    "                   oTextbox.value = arrMatches[0];\r\n",
                    "                   textboxSelect(oTextbox, iLen, oTextbox.value.length);\r\n",
                    "                  \r\n",
                    "                   if (arrMatches.length > 1)\r\n",
                    "                   {\r\n",
                    "                        frame.style.display = 'inline';\r\n",
                    "                        frame.height = '100';\r\n",
                    "                        \r\n",
                    "                        frame.contentWindow.document.body.innerHTML = '';\r\n",
                    "                        for (var i = 0; i < arrMatches.length; i++)\r\n",
                    "                        {\r\n",
                    "                            frame.contentWindow.document.body.innerHTML += '<div style=\"width: 100%; cursor: default\" onmouseover=\"this.style.backgroundColor=\\'#316AC5\\'; this.style.color=\\'white\\';\" onmouseout=\"this.style.backgroundColor=\\'\\'; this.style.color=\\'black\\';\" onclick=\"parent.document.getElementById(\\'' + id + '_textBox\\').value = this.innerHTML\">' + arrMatches[i] + '</div>';\r\n",
                    "                        }\r\n",
                    "                        \r\n",
                    "                        frame.contentWindow.document.body.style.backgroundColor = 'white';\r\n",
                    "                        frame.contentWindow.document.onclick = function() { document.getElementById(id + '_autoCompleteFrame').style.display = 'none'; };\r\n",
                    "                   }  \r\n",
                    "                }  \r\n",
                    "                \r\n",
                    "                return false;\r\n",
                    "        }        \r\n",
                    "    }\r\n",
                    "</script>\r\n",
                    "");
                Page.ClientScript.RegisterClientScriptBlock(typeof(string), "__DoAutoComplete", script);
            }

            if (!Page.ClientScript.IsClientScriptBlockRegistered(MakeUniqueID("data")))
            {
                Page.ClientScript.RegisterClientScriptBlock(typeof(string), MakeUniqueID("data"), string.Format("<script language=\"javascript\" type=\"text/javascript\">document.{0}_data = {1}</script>", MakeUniqueID(null), ToJsStringArray(AutoCompleteData)));
            }

            #endregion
        }

        protected override void RenderContents(HtmlTextWriter output)
        {
            output.WriteLine(string.Format("<div onmouseleave=\"document.getElementById('{0}').style.display = 'none';\" style=\"width:{1}\" >", MakeUniqueID("autoCompleteFrame"), Width));
            textBox.RenderControl(output);
            output.WriteLine("<br />");
            autoCompleteFrame.RenderControl(output);
            output.WriteLine("</div>");
        }

        #endregion
    }
}

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