public ActionResult Upload()
    {
      string imgurl = "";
      foreach (string key in Request.Files)
      {
        //這里只測試上傳第一張圖片file[0]
        HttpPostedFileBase file0 = Request.Files[key];
        //轉換成byte,讀取圖片MIME類型
        Stream stream;
        int size = file0.ContentLength / 1024; //文件大小KB
        if (size > 1024)
        {
          return Content(ReturnMsg(Enum_Return.失敗, "圖片不能超過1M：", null));
        }
        byte[] fileByte = new byte[2];//contentLength，這里我們只讀取文件長度的前兩位用于判斷就好了，這樣速度比較快，剩下的也用不到。
        stream = file0.InputStream;
       stream.Read(fileByte, 0, 2);//contentLength，還是取前兩位
        //獲取圖片寬和高
        //System.Drawing.Image image = System.Drawing.Image.FromStream(stream);
        //int width = image.Width;
        //int height = image.Height;
        string fileFlag = "";
        if (fileByte != null && fileByte.Length > 0)//圖片數據是否為空
        {
          fileFlag = fileByte[0].ToString()  fileByte[1].ToString();
        }
        string[] fileTypeStr = { "255216", "7173", "6677", "13780" };//對應的圖片格式jpg,gif,bmp,png
        if (fileTypeStr.Contains(fileFlag))
        {
          string action = Request["action"];
          string path = "/uploads/";
          switch (action)
          {
            case "headimage":
              path  = "headimage/";
              break;
            case "blogtype":
              path  = "blogtype/";
              break;
          }
          string fullpath = path  UserInfo.userID  "/";
          if (!Directory.Exists(Server.MapPath(fullpath)))
          {
            Directory.CreateDirectory(Server.MapPath(fullpath));
          }
          Request.Files[key].SaveAs(Server.MapPath(fullpath  Request.Files[key].FileName));
          imgurl = fullpath  Request.Files[key].FileName;
        }
        else
        {
          return Content(ReturnMsg(Enum_Return.失敗, "圖片格式不正確：" fileFlag, null));
        }
        stream.Close();
      }
      return Content(ReturnMsg(Enum_Return.成功, "上傳成功", imgurl));
    }

public void ProcessRequest(HttpContext context)
  {
    context.Response.ContentType = "application/json";
    HttpPostedFile _upfile = context.Request.Files["File"];
    if (_upfile.ContentLength < 500000)
    {
      if (string.IsNullOrEmpty(_upfile.FileName))
      {
         context.Response.Write("請上傳圖片");
      }
      string fileFullname = _upfile.FileName;
      string dataName = DateTime.Now.ToString("yyyyMMddhhmmss");
      string fileName = fileFullname.Substring(fileFullname.LastIndexOf("\\")  1);
      string type = fileFullname.Substring(fileFullname.LastIndexOf(".")  1);
      if (type == "bmp" || type == "jpg" || type == "gif" || type == "JPG" || type == "BMP" || type == "GIF")
      {
        _upfile.SaveAs(HttpContext.Current.Server.MapPath("photo")  "\\"  dataName  "."  type);
        HttpCookie cookie = new HttpCookie("photo");
        context.Response.Write("上傳成功");
      }
      else
      {
        context.Response.Write("支持格式：|jpg|gif|bmp|");
      }
    }
    else
    {
      context.Response.Write("你的圖片已經超過500K的大小！");
    }
  }