0.引言

1.起因

jQuery UI Autocomplete Combobox 配 ASP.NET DropDownList

一开始使用Autocomplete做了一个自动补全的文本框，如上图。后来因业务需要希望能在这个文本框的边上做个下拉列表按钮，一按就展开所有支持自动补全的选项。于是在网上搜索了好久，需找类似的插件，最后却回到了原点 jQuery UI Autocomplete Combobox 配 ASP.NET DropDownList

。原来jQuery UI 官网Autocomplete介绍里面就有个叫做Combobox的东西（见下图）。

(Combobox)

因为官网上的Combobox用的是Select+Option，我一开始还犯愁，真正用的时候发现它其实可以完美匹配DropDownList。

2.最终效果

1.代码&分析

1.代码

官网Combobox示例代码

<!doctype html>

<html lang="en">

<head>

  <meta charset="utf-8">

  <title>jQuery UI Autocomplete - Combobox</title>

  <link rel="stylesheet" href="//code.jquery.com/ui/1.11.4/themes/smoothness/jquery-ui.css">

  <script src="//code.jquery.com/jquery-1.10.2.js"></script>

  <script src="//code.jquery.com/ui/1.11.4/jquery-ui.js"></script>

  <link rel="stylesheet" href="/resources/demos/style.css">

  <style>

  .custom-combobox {

    position: relative;

    display: inline-block;

  }

  .custom-combobox-toggle {

    position: absolute;

    top: 0;

    bottom: 0;

    margin-left: -1px;

    padding: 0;

  }

  .custom-combobox-input {

    margin: 0;

    padding: 5px 10px;

  }

  </style>

  <script>

  (function( $ ) {

    $.widget( "custom.combobox", {

      _create: function() {

        this.wrapper = $( "<span>" )

          .addClass( "custom-combobox" )// 此处设置整体span的class

          .insertAfter( this.element );

        this.element.hide();

        this._createAutocomplete();

        this._createShowAllButton();

      },

      _createAutocomplete: function() {

        var selected = this.element.children( ":selected" ),

          value = selected.val() ? selected.text() : "";

        this.input = $( "<input>" )

          .appendTo( this.wrapper )

          .val( value )

          .attr( "title", "" )

          .addClass( "custom-combobox-input ui-widget ui-widget-content ui-state-default ui-corner-left" )//此处设置input的class

          .autocomplete({

            delay: 0,

            minLength: 0,

            source: $.proxy( this, "_source" )

          })

          .tooltip({

            tooltipClass: "ui-state-highlight"

          });

        this._on( this.input, {

          autocompleteselect: function( event, ui ) {

            ui.item.option.selected = true;

            this._trigger( "select", event, {

              item: ui.item.option

            });

          },

          autocompletechange: "_removeIfInvalid"

        });

      },

      _createShowAllButton: function() {

        var input = this.input,

          wasOpen = false;

        $( "<a>" )

          .attr( "tabIndex", -1 )

          .attr( "title", "Show All Items" )

          .tooltip()

          .appendTo( this.wrapper )

          .button({

            icons: {

              primary: "ui-icon-triangle-1-s"

            },

            text: false

          })

          .removeClass( "ui-corner-all" )

          .addClass( "custom-combobox-toggle ui-corner-right" )// 此处设置下拉列表按钮的class

          .mousedown(function() {

            wasOpen = input.autocomplete( "widget" ).is( ":visible" );

          })

          .click(function() {

            input.focus();

            // Close if already visible

            if ( wasOpen ) {

              return;

            }

            // Pass empty string as value to search for, displaying all results

            input.autocomplete( "search", "" );

          });

      },

      _source: function( request, response ) {

        var matcher = new RegExp( $.ui.autocomplete.escapeRegex(request.term), "i" );

        response( this.element.children( "option" ).map(function() {

          var text = $( this ).text();

          if ( this.value && ( !request.term || matcher.test(text) ) )

            return {

              label: text,

              value: text,

              option: this

            };

        }) );

      },

         // 移除input中补全失败的内容

      _removeIfInvalid: function( event, ui ) {

        // Selected an item, nothing to do

        if ( ui.item ) {

          return;

        }

        // Search for a match (case-insensitive)

        var value = this.input.val(),

          valueLowerCase = value.toLowerCase(),

          valid = false;

        this.element.children( "option" ).each(function() {

          if ( $( this ).text().toLowerCase() === valueLowerCase ) {

            this.selected = valid = true;

            return false;

          }

        });

        // Found a match, nothing to do

        if ( valid ) {

          return;

        }

        // Remove invalid value

        this.input

          .val( "" )

          .attr( "title", value + " didn't match any item" )

          .tooltip( "open" );

        this.element.val( "" );

        this._delay(function() {

          this.input.tooltip( "close" ).attr( "title", "" );

        }, 2500 );

        this.input.autocomplete( "instance" ).term = "";

      },

      _destroy: function() {

        this.wrapper.remove();

        this.element.show();

      }

    });

  })( jQuery );

  $(function() {

    $( "#combobox" ).combobox();

    $( "#toggle" ).click(function() {

      $( "#combobox" ).toggle();

    });

  });

  </script>

</head>

<body>

<div class="ui-widget">

  <label>Your preferred programming language: </label>

  <select id="combobox">

    <option value="">Select one...</option>

    <option value="ActionScript">ActionScript</option>

    <option value="AppleScript">AppleScript</option>

    <option value="Asp">Asp</option>

    <option value="BASIC">BASIC</option>

    <option value="C">C</option>

    <option value="C++">C++</option>

    <option value="Clojure">Clojure</option>

    <option value="COBOL">COBOL</option>

    <option value="ColdFusion">ColdFusion</option>

    <option value="Erlang">Erlang</option>

    <option value="Fortran">Fortran</option>

    <option value="Groovy">Groovy</option>

    <option value="Haskell">Haskell</option>

    <option value="Java">Java</option>

    <option value="JavaScript">JavaScript</option>

    <option value="Lisp">Lisp</option>

    <option value="Perl">Perl</option>

    <option value="PHP">PHP</option>

    <option value="Python">Python</option>

    <option value="Ruby">Ruby</option>

    <option value="Scala">Scala</option>

    <option value="Scheme">Scheme</option>

  </select>

</div>

<button id="toggle">Show underlying select</button>

</body>

</html>

配合效果图和前台页面生成的 DOM 节点来分析

1.原来的select被隐藏了

2.外面是个span标签，内部是一个input标签（输入框）和一个a标签（下拉按钮）

它们三的class分别对应为

span	.custom-combobox
input	.custom-combobox-input
a	.custom-combobox-toggle

可以通过它们的类名对它们进行操作和样式修改

3.http://api.jqueryui.com/autocomplete/ 有关Autocomplete插件更多的资料

2.配合DropDownList

只需将select标签换成一个DropDownList即可

<asp:DropDownListID="combobox"runat="server"></asp:DropDownList>

然后在C#中绑定想要自动填充的内容

combobox.AutoPostBack = true;

string sqlstr = "SELECT DISTINCT Config_Type FROM [EMS].[dbo].[EMS_Config]";

using(var dt=SQLLocalEMS.ExecuteQuery(sqlstr, CommandType.Text))

{

    if(dt!=null)

    {

        combobox.DataSource = dt;

        combobox.DataTextField = "Config_Type";

        combobox.DataValueField = "Config_Type";

        combobox.DataBind();

    }

}

2.重复插入 combobox 的bug

1.bug描述

实际使用时发现每一次PostBack都会导致组成 combobox 的各DOM 节点被重复插入到页面底部

如下图

1：初始绑定 combobox时生成的

2、3、4：PostBack页面时重复插入的

4：当前真实使用的

2.临时修复方法

通过在每次插入新的 combobox 前，将之前插入的相关 DOM remove()

_create: function() {

    //修复重复Insert的bug

    $(".ui-helper-hidden-accessible").remove();

    $(".ui-autocomplete").remove();

    this.wrapper = $( "<span>" )

      .addClass( "custom-combobox col-lg-11 padding0" )// 此处设置整体span的class

      .insertAfter( this.element );

    this.element.hide();

    this._createAutocomplete();

    this._createShowAllButton();

  },

来自为知笔记(Wiz)

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jQuery UI Autocomplete Combobox 配 ASP.NET DropDownList