.net文件上传，客户端用jquery file upload

<%@ WebHandler Language="C#" Class="Handler" %>

using System;
using System.Web;


using System.IO;


public class Handler : IHttpHandler {

    /// <summary>
    /// 上传文件夹
    /// </summary>
    private const string UPLOAD_FOLDER = "~/UploadFile/";

    public void ProcessRequest(HttpContext context)
    {
        int resultVal = (int)ReturnVal.Failed;
        try
        {
            HttpPostedFile myFile = context.Request.Files[0];

            if (myFile != null)
            {
                if (myFile.InputStream.Length != 0)
                {
                    string originalFileName = Path.GetFileName(myFile.FileName);     //原文件名                        
                    string newFileName = string.Format("{0}_{1}", Guid.NewGuid(), originalFileName);   //新文件名---组成形式：  GUID + 下划线 + 原文件名
                    string fileAbsPath = context.Server.MapPath(UPLOAD_FOLDER) + newFileName;   //绝对路径

                    myFile.SaveAs(fileAbsPath);

                    resultVal = (int)ReturnVal.Succeed;
                }
                else
                {
                    resultVal = (int)ReturnVal.FileEmpty;
                }
            }
            else
            {
                resultVal = (int)ReturnVal.NotSelected;
            }
        }
        catch (Exception)
        {
            resultVal = (int)ReturnVal.Failed;
        }
        finally
        {
            context.Response.Write(resultVal);
        }
    }

    #region## 返回值
    /// <summary>
    /// 返回值
    /// </summary>
    private enum ReturnVal : int
    {
        /// <summary>
        /// 不能上传 0 K大小的文件
        /// </summary>
        FileEmpty = -2,

        /// <summary>
        /// 未选中文件
        /// </summary>
        NotSelected = -1,

        /// <summary>
        /// 上传失败
        /// </summary>
        Failed = 0,

        /// <summary>
        /// 成功
        /// </summary>
        Succeed = 1

    }
    #endregion
    public bool IsReusable
    {
        get
        {
            return false;
        }
    }

}