基于extjs4.2
controller

//存储数据的类
public class DataLink {
    public string Name { get; set; }
    public string Address { get; set; }
    public int Age { get; set; }
}
public ActionResult MessageBack(string username)
{   
    //声明泛型
    List<DataLink> resultData = new List<DataLink>();
    //存储数据到对象中
    resultData.Add(new DataLink() { Name = "tetse", Age = 19, Address = "ly" });
    //把对象序列化为string
    string rs = Newtonsoft.Json.JsonConvert.SerializeObject(resultData);
    //返回前端
    return Content(rs);
}