使用ajax上傳文件

      ajax如下

function doUpload() {
     var fd= new FormData($( "#uploadForm" )[0]);  //uploadForm為from表單id
     $.ajax({
          url: 'XXXXXX' ,
          type: 'post',
          data: fd,
          async: false,
          cache: false,
          processData: false,  //  //這兩行代碼一定要加上  (默认: true) 默认情况下,发送到服务器的数据（即data参数）将被转换为字符串以配合默认内容类型
                                       //  "application/x-www-form-urlencoded"。                                       //如果要发送 DOM 树信息或其它不希望转换的信息，请设置为 false。
          contentType: false, //默認為string類型   "application/x-www-form-urlencoded"
          success: function (returndata) {
              alert(returndata);
          },
          error: function (returndata) {
              alert(returndata);
          }
     });
}

 

例子: 

<form id="form1" runat="server">
        <div>
            &nbsp;<br />
            <input id="fup_two" name="fup_two" type="file" />

            <input id="tryone" type="button" value="嘗試第二個" onclick="a()" />
        </div>

</form>

 

//注意低版本的jquery不支持.

    <script>
        function a() {
            var file = $("#fup_two")[0].files[0];
            if (file.size > 1200000000) {
                alert("文件過大,不能發送.");
                return;
            }
            else {
                //buzhichi jquery 1.4......
                var fd = new FormData($("#form1")[0]);
                $.ajax({
                    type: "post",
                    url: "ashx/ajax.ashx?type=up",
                    data: fd,
                    dataType: "text",
                    async: false,
                    cache: false,
                    processData: false,//must 加上(默认: true) 默认情况下,发送到服务器的数据（即data参数）将被转换为字符串以配合默认内容类型 "application/x-www-form-urlencoded"。
                    //如果要发送 DOM 树信息或其它不希望转换的信息，请设置为 false。
                    contentType: false,//must 加上processData contentType必須配合使用
                    success: function (data) {
                        alert(1);
                        alert(data);
                    },
                    error: function (data) {
                        alert(2);
                    }
                });
            }
        }
    </script>

 

在一般處理程序中,關鍵代碼如下.

        public void ProcessRequest(HttpContext context)
        {
            context.Response.ContentType = "text/plain";
            string types = context.Request.Params["type"];

            switch (types)
            {
                case "ajax":
                    Getstr();
                    break;
                case "up":
                    up(context);
                    break;
                default:
                    break;
            }
        }

        public void Getstr()
        {
            HttpContext.Current.Response.Write("asaf");
        }
        public void up(HttpContext context)
        {
            HttpPostedFile hpf = context.Request.Files["fup_two"];
            string strs = HttpContext.Current.Server.MapPath("Temp");
            string filename=DateTime.Now.ToLongDateString()+Path.GetExtension(hpf.FileName);
            hpf.SaveAs(strs+"/"+filename);
            if (File.Exists(strs+"/"+ filename))
            {
                context.Response.Write("上傳成功!");
            }
            else
            {
                context.Response.Write("上傳失敗!");
            }
        }