使用AutoComplete时,ContextKey传值总为空的问题!

asp:

 <script type="text/javascript"> 
function OnTxtPersonInfoKeyDown() { 
var val = document.getElementById("<%=TextBox1.ClientID %>").value; 
var NameClientID = "<%=AutoCompleteExtender1.ClientID %>"; 
var acName = $find(NameClientID); 
if (acName != null) { 
acName.set_contextKey(val); 
} 
} 
function OnTxtPersonInfoKeyDown2() { 
var val = document.getElementById("<%=TextBox1.ClientID %>").value; 
var NameClientID = "<%=AutoCompleteExtender2.ClientID %>"; 
var acName = $find(NameClientID); 
if (acName != null) { 
acName.set_contextKey(val); 
} 
} 
</script> 
</head> 
<body> 
<form id="form1" runat="server"> 
<div> 
<asp:ToolkitScriptManager ID="ToolkitScriptManager1" runat="Server" /> 
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox> 
<asp:AutoCompleteExtender ID="AutoCompleteExtender1" runat="server" 
TargetControlID="TextBox1" 
CompletionSetCount="10" 
EnableCaching="false" 
FirstRowSelected="true" 
UseContextKey="True" 
MinimumPrefixLength="0" 
CompletionInterval="100" 
ServicePath="webservice.asmx" 
ServiceMethod="GetData"> 
</asp:AutoCompleteExtender> 
<br /> 
<asp:TextBox ID="TextBox2" runat="server"></asp:TextBox> 
<asp:AutoCompleteExtender ID="AutoCompleteExtender2" runat="server" 
TargetControlID="TextBox2" 
CompletionSetCount="10" 
EnableCaching="false" 
FirstRowSelected="true" 
UseContextKey="True" 
MinimumPrefixLength="0" 
CompletionInterval="100" 
BehaviorID="AutoCompleteEx"
ServicePath="webservice.asmx" 
ServiceMethod="GetEnglishName"> 

</asp:AutoCompleteExtender> 

cs:

    protected void Page_Load(object sender, EventArgs e)
    {
        TextBox1.Attributes.Add("onkeydown", "return OnTxtPersonInfoKeyDown();");
        TextBox2.Attributes.Add("onkeydown", "return OnTxtPersonInfoKeyDown2();"); 
    }

        webservice.cs

            [WebMethod]
    [ScriptMethod]
    public string[] GetEnglishName(string prefixText, int count, string contextKey)
    {
        string xx = contextKey;   //**这里传的值总为空,求大神指点**
            DataSet ds = bc.GetDataSet("select ID,BidderName from 投标人信息 where Name ='" + contextKey + "'", "投标人信息");


            List<string> suggestions = new List<string>();//声明一泛型集合
            suggestions.Clear();
            if (ds.Tables[0].Rows.Count > 0)
            {
                for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
                {
                    suggestions.Add(ds.Tables[0].Rows[i][1].ToString());
                }
            }
            return suggestions.ToArray();
    } 

function OnTxtPersonInfoKeyDown2() {

 var val = document.getElementById("<%=TextBox1.ClientID %>").value; ///////////////
var NameClientID = "<%=AutoCompleteExtender2.ClientID %>"; 
var acName = $find(NameClientID); 
if (acName != null) { 
acName.set_contextKey(val); 
} 
} 

=====>ID搞错了,对TextBox2

 var val = document.getElementById("<%=TextBox2.ClientID %>").value; ///////////////