title: How to get searchString in ASP.NET with jqGrid
body: <p>front-end:</p>
  
  <pre><code>$("#UsersGrid").jqGrid({
      url: "jqGridHandler.ashx",
      mtype: 'post',
      datatype: 'json',
      height: 250,
      colNames: ['CardNumber', 'CardType', 'CardGrade', 'CanUseMoney', 'MemberName'],
      colModel: [
          { name: 'CardNumber', index: 'CardNumber', width: 150, search: true,
              searchoptions: { sopt: ['eq']}},
          { name: 'CardType', width: 150},
          { name: 'CardGrade', width: 150 },
          { name: 'CanUseMoney', width: 150 },
          { name: 'MemberName', width: 150, search: true,
              searchoptions: { sopt: ['eq']} }
      ],
      rowNum: 10,
      rowList: [10, 20, 30],
      sortname: 'CardNumber',
      viewrecords: true,
      sortorder: 'asc',
      caption: 'card',
      pager: $("#pager")
  }).navGrid('#pager',
      { search: true, edit: false, add: false, del: false, searchtext: "search" });
  </code></pre>
  
  <p>jqGridHandler.ashx:</p>
  
  <pre class="lang-cs prettyprint-override"><code>HttpRequest request = context.Request;
  
  string _searchsrt = request["searchString"];
  </code></pre>
  
  <p>I would like to get <code>searchString</code> in "jqGridHandler.ashx", but I found it is ""
  how to do? can any one help me out? tks!</p>