C#上传图片方法

该案例是mvc下的demo，支持单张图片上传。

public ActionResult Upload()
    {
      string imgurl = "" ;
      foreach ( string key in Request.Files)
      {
        //这里只测试上传第一张图片file[0]
        HttpPostedFileBase file0 = Request.Files[key];
        //转换成byte,读取图片MIME类型
        Stream stream;
        int size = file0.ContentLength / 1024; //文件大小KB
        if (size > 1024)
        {
          return Content(ReturnMsg(Enum_Return.失败, "图片不能超过1M：" , null ));
        }
        byte [] fileByte = new byte [2]; //contentLength，这里我们只读取文件长度的前两位用于判断就好了，这样速度比较快，剩下的也用不到。
        stream = file0.InputStream;
       stream.Read(fileByte, 0, 2); //contentLength，还是取前两位
        //获取图片宽和高
        //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) //图片数据是否为空
        {
          fileFlag = fileByte[0].ToString()  fileByte[1].ToString();
        }
        string [] fileTypeStr = { "255216" , "7173" , "6677" , "13780" }; //对应的图片格式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.失败, "图片格式不正确：" fileFlag, null ));
        }
        stream.Close();
      }
      return Content(ReturnMsg(Enum_Return.成功, "上传成功" , imgurl));
    }

一般处理程序

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( "请上传图片" );
      }
      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( "上传成功" );
      }
      else
      {
        context.Response.Write( "支持格式：|jpg|gif|bmp|" );
      }
    }
    else
    {
      context.Response.Write( "你的图片已经超过500K的大小！" );
    }
  }