ajax调用ajax

namespace Unit95
{
[ServiceContract(Namespace = "")]
[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
[JavascriptCallbackBehavior(UrlParameterName ="a")]
public class ajaxService
{
SqlConnection con = new SqlConnection("Data Source=.;Initial Catalog=unit6;Integrated Security=True");
// 要使用 HTTP GET，请添加 [WebGet] 特性。(默认 ResponseFormat 为 WebMessageFormat.Json)
// 要创建返回 XML 的操作，
// 请添加 [WebGet(ResponseFormat=WebMessageFormat.Xml)]，
// 并在操作正文中包括以下行:
// WebOperationContext.Current.OutgoingResponse.ContentType = "text/xml";
[OperationContract]
[WebGet(ResponseFormat = WebMessageFormat.Json)]
public string GetListData(string id="")
{
string sql = "select m.*,[diqubiaoName] from mendian m inner join diqubiao d on m.diqubiaoID=d.diqubiaoID where 1=1 ";
if (!string.IsNullOrWhiteSpace(id))
sql += " and mendianID="+id;
SqlDataAdapter ada = new SqlDataAdapter(sql, con);
DataTable table = new DataTable();
ada.Fill(table);

// 在此处添加操作实现
return JsonConvert.SerializeObject(table);
}
[OperationContract]
[WebGet(ResponseFormat = WebMessageFormat.Json)]
public int deleteByID(int id)
{
con.Open();
SqlCommand cmd = new SqlCommand("delete from mendian where mendianID=" + id, con);
return cmd.ExecuteNonQuery();
}

[OperationContract]
[WebGet(ResponseFormat = WebMessageFormat.Json)]
public string GetDiQu()
{
string sql = "select * from diqubiao ";

SqlDataAdapter ada = new SqlDataAdapter(sql, con);
DataTable table = new DataTable();
ada.Fill(table);

// 在此处添加操作实现
return JsonConvert.SerializeObject(table);
}

// 在此处添加更多操作并使用 [OperationContract] 标记它们
}