asp.net 模糊查询（传入第三个参数）

html页

         <ajaxToolkit:AutoCompleteExtender ID="AutoCompleteExtender2" runat="server" ServicePath="~/DataService.asmx"
                    MinimumPrefixLength="1" CompletionInterval="500" EnableCaching="true" TargetControlID="txtChannel"
                    ServiceMethod="GetChannel" FirstRowSelected="True" CompletionListElementID="listPlacement"
                    CompletionListCssClass="ajxstyle">
                </ajaxToolkit:AutoCompleteExtender>
                <div id="listPlacement" runat="server" style="height: 350px; overflow: auto; display: none;" />
               渠道模糊查询： <asp:TextBox ID="txtChannel" runat="server" Width="350px" ToolTip="输入进行模糊查询"
                    OnTextChanged="txtChannel_TextChanged" onkeydown="return OnTxtKeyDown();" AutoPostBack="True" />

js获取并设置第三个参数：

        //AutoCompleteExtender传递第三个参数
        function OnTxtKeyDown() {
            var acNameClientId = "<%=AutoCompleteExtender2.BehaviorID %>";
            var acName = $find(acNameClientId);
            if (acName != null) {
                var orderID = $("select[id*='DrpOrder']").val();
                if (!isNaN(orderID)) {
                    acName.set_contextKey(orderID);
                }
            }
        }

后台方法,文本框内容改变时：

 protected void txtChannel_TextChanged(object sender, EventArgs e)
    {
        try
        {
            string selectValue = txtChannel.Text.ToString();
            if (!string.IsNullOrEmpty(selectValue))
            {
               string chanId= selectValue.Substring(selectValue.LastIndexOf('[')+1, selectValue.Length-selectValue.LastIndexOf('[')-2);
               DrpChannel.SelectedValue = chanId;
               drpChannelChan();
            }
        }
        catch
        {
            ScriptManager.RegisterStartupScript(this, this.GetType(), "s", "alert('未在本订单查到["+txtChannel.Text.Trim()+"]！');", true); 
        }    
    }

webService的方法，其中contextKey为第三个参数

    [System.Web.Script.Services.ScriptMethod]
    [WebMethod]
    public string[] GetChannel(string prefixText, int count, string contextKey)
    {

        if (!string.IsNullOrEmpty(contextKey))
        {
            string sql = string.Format(@"
                SELECT CHANNEL_NAME FROM (
                    SELECT  
                             '(' || C.QX_CHANNEL_NAME || ')' || C.NAME ||'['||C.ID||']' CHANNEL_NAME
                        FROM TL_REQUISITION A, TL_USER_INFO B, V_CHANNEL_PATH C
                       WHERE A.ORDER_ID = {0}
                         AND A.USER_ID = B.ID
                         AND B.CHANNEL_ID = C.ID
                         AND (A.STATUS <> '草稿' AND A.STATUS NOT LIKE '%退回%')
                         AND (A.IS_SCAN IS NULL OR A.IS_SCAN = 0)
                    ORDER BY C.QX_CHANNEL_NAME
                )WHERE CHANNEL_NAME LIKE '%{1}%'", Convert.ToInt32(contextKey), prefixText);

            ISqlQuery isqlQuery = AppHelper.GetService<ISqlQuery>();
            isqlQuery.Sql = sql;
            DataTable dt = isqlQuery.Execute();

            string[] strArray = null;
            if (dt != null)
            {
                if (dt.Rows.Count > 0)
                {
                    List<String> list = new List<String>();

                    foreach (DataRow item in dt.Rows)
                    {
                        list.Add(item[0].ToString());

                    }
                    strArray = list.ToArray();
                }
            }
            return strArray;
        }
        else return null;
    }