Jquery调用Webservice传递Json数组

{'Employee': [{'name':'John','sex':'man','age':'25'},{'name':'Tom','sex':'man','age':'21'}]}

//jquery 调用webService导入数据
function LoadData() {
  var studentData = CollectionData();
  $.ajax({
url: "ImportDataService.asmx/ImportStu",
type: "post",
contentType: "application/json;charset=utf-8",
dataType: "json",
data: "{'students':[{'name':'KoBe ','sex':'boy','age':'20'},{'name':'Mary','sex':'girl','age':'19'}]}",
success: function(result) {
    alert(result.d);
},
error: function(e) {
    alert(e.responseText);
}
      });
  }

/// <summary>
///
/// </summary>
/// <param name="students"></param>
/// <returns></returns>
 [WebMethod]
 [ScriptMethod(ResponseFormat=ResponseFormat.Json)]
  public string ImportStu(Dictionary<string,string> []students)
{
  if (students.Length == 0)
  {
      return "没有任何数据!";
  }
  else
  {
try
{
foreach (Dictionary<string, string> stu in students)
{
    //构造一个新的Student对象。
    Student student = new Student();

    //为新构造的Student对象属性赋值。
    foreach (string key in stu.Keys)
    {
        switch (key)
        {
  case "name":
      student.Name = stu[key];
      break;
  case "sex":
      student.Sex = stu[key];
      break;
  case "age":
      int age;
      if (Int32.TryParse(stu[key], out age))
      {
student.Age = age;
      }
      else
      {
student.Age = 0;
      }
      break;
  default:
      break;
        }
    }
}
return "导入学生成功!";
      }
      catch
      {
throw new Exception("导入学生失败!");
      }
  }
}