jQuery UI Autocomplete Combobox 配 ASP.NET DropDownList

0.引言

1.起因

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

。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>

View Code

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)