.NET MVC5簡介（三）Result

Ajax請求數據響應格式，一個醒目組必須是同意的，前端才知道怎麼應付，還有很多其他情況，比如異常了，有ExceptionFilter，按照固定格式返回，比如沒有許可權，Authorization，按照固定格式返回。

Http請求的本質：

　　請求--應答式，響應可以那麼豐富？不同的類型其實方式一樣的，只不過有個ContenetType的差別，html--text/html、json--application/json、xml/application/xml、js--application/JavaScript、ico--image/x-icon、image/gif、image/jepg、image/png.....

　　這個等於是Http協議約定，Web框架和瀏覽器共同支持的。其實就是伺服器告訴瀏覽器如何處理這個數據，從頁面下載pdf或者頁面展示pdf靠的就是ContentType，application/pdf、application/octet-stream。

MVC各種Result的事，JsonResult實際上就是JsonResult，繼承ActionResult，然後重寫ExecuteResult方法，指定ContentType為application/json，然後將Data序列化成字元串寫入stream，我們可以隨意擴展，只需要把數據放到response，指定好ContentType

ContentType對照表：http://tool.oschina.net/commons

/// <summary>
/// 返回ActionResult--MVC框架會執行其ExecuteResult方法---
/// </summary>
/// <returns></returns>
public JsonResult JsonResultIn()
{
    return Json(new AjaxResult()
    {
        Result = DoResult.Success,
        DebugMessage = "這裡是JsonResult"
    }, JsonRequestBehavior.AllowGet);
}

比如我們現在來擴展個NewtonJsonResult

public class NewtonJsonResult : ActionResult
{
    private object Data = null;
    public NewtonJsonResult(object data)
    {
        this.Data = data;
    }
    public override void ExecuteResult(ControllerContext context)
    {
        HttpResponseBase response = context.HttpContext.Response;
        response.ContentType = "application/json";
        response.Write(Newtonsoft.Json.JsonConvert.SerializeObject(this.Data));
    }
}

調用的時候：

 /// <summary>
 /// 返回ActionResult--MVC框架會執行其ExecuteResult方法---
 /// </summary>
 /// <returns></returns>
 public NewtonJsonResult JsonResultNewton()
 {
     return new NewtonJsonResult(new AjaxResult()
     {
         Result = DoResult.Success,
         DebugMessage = "這裡是JsonResult"
     });
 }

AjaxResult：

 public class AjaxResult
 {
     public AjaxResult()
     { }
     public string DebugMessage { get; set; }
     public string PromptMsg { get; set; }
     public DoResult Result { get; set; }
     public object RetValue { get; set; }
     public object Tag { get; set; }
 }
 public enum DoResult
 {
     Failed = 0,
     Success = 1,
     OverTime = 2,
     NoAuthorization = 3,
     Other = 255
 }

自定義擴展XMLResult

 /// <summary>
 /// 自定義擴展XML格式result
 /// </summary>
 public class XmlResult : ActionResult
 {
     private object _data;

     public XmlResult(object data)
     {
         _data = data;
     }

     public override void ExecuteResult(ControllerContext context)
     {
         var serializer = new XmlSerializer(_data.GetType());
         var response = context.HttpContext.Response;
         response.ContentType = "text/xml";
         serializer.Serialize(response.Output, _data);
     }
 }

public XmlResult XmlResult()
{
    return new XmlResult(new AjaxResult()
    {
        Result = DoResult.Success,
        DebugMessage = "這裡是JsonResult"
    });
}

 現在，我們不寫返回值，直接寫入stream

/// </summary>
public void JsonResultVoid()
{
    HttpResponseBase response = base.HttpContext.Response;
    response.ContentType = "application/json";
    response.Write(
        Newtonsoft.Json.JsonConvert.SerializeObject(new AjaxResult()
        {
            Result = DoResult.Success,
            DebugMessage = "這裡是JsonResult"
        }));
}