文件上传下载代码

using System;
using System.Web;
using System.IO;
using System.Text;
using System.Web.UI.WebControls;

namespace BD
{
    public class FileUtil
    {
        #region 文件路径

        /// <summary>
        /// 得到没有后缀的文件名
        /// </summary>
        /// <param name="_FullName"></param>
        /// <returns></returns>
        public static string GetFileNameWithoutExtension(string _FullName)
        {
            return Path.GetFileNameWithoutExtension(_FullName);
        }

        /// <summary>
        /// 得到文件的扩展名
        /// </summary>
        /// <param name="_FullName"></param>
        /// <returns></returns>
        public static string GetExtension(string _FullName)
        {
            return Path.GetExtension(_FullName);
        }

        /// <summary>
        /// 得到文件名
        /// </summary>
        /// <param name="_FullName"></param>
        /// <returns></returns>
        public static string GetFileName(string _FullName)
        {
            return Path.GetFileName(_FullName);
        }

        #endregion

        #region 文件上传下载删除

        /// <summary>
        /// 上传文件
        /// </summary>
        /// <param name="_DevicePath">需要保存到的根路径</param>
        /// <param name="_FileUpload">文件上传控件</param>
        /// <param name="_NewFileName">返回一个生成的文件名</param>
        /// <returns></returns>
        public static bool UpLoadFile(string _DevicePath, FileUpload _FileUpload, out string _NewFileName)
        {
            _NewFileName = string.Empty;
            StringBuilder sbPath = new StringBuilder();
            sbPath.Append(_DevicePath);
            //检查目录是否存在
            if (!Directory.Exists(sbPath.ToString()))
            {
                try
                {
                    //如果目录不存在就创建目录
                    Directory.CreateDirectory(sbPath.ToString());
                }
                catch (Exception)
                {
                    return false;
                }
            }
            //得到上传文件全路径
            string FullName = _FileUpload.PostedFile.FileName;
            //得到扩展名
            string FileExtension = GetExtension(FullName);
            //随机生成文件名
            Random random = new Random(DateTime.Now.Millisecond);
            string FileName = DateTime.Now.ToString("yyyyMMddHHmmss") + DateTime.Now.Millisecond.ToString() + random.Next(int.MaxValue).ToString();
            _NewFileName = FileName;
            //增加随机生成的文件名
            sbPath.Append(FileName);
            //加上后缀名
            sbPath.Append(FileExtension);
            try
            {
                //上传到指定文件夹
                _FileUpload.PostedFile.SaveAs(sbPath.ToString());
            }
            catch (Exception)
            {
                return false;
            }
            return true;
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="_Path"></param>
        public static void DownloadFileBinary(string _Path)
        {
            //新建一个只读的文件流
            FileStream fstream = new FileStream(_Path, FileMode.Open);
            //设置基本信息
            HttpContext.Current.Response.Buffer = false;
            HttpContext.Current.Response.AddHeader("Connection", "KeepAlive");
            HttpContext.Current.Response.ContentType = "image/jpeg";
            HttpContext.Current.Response.AddHeader("Content-Disposition", "attachment;filename=" + System.IO.Path.GetFileName(_Path));
            HttpContext.Current.Response.AddHeader("Content-Lengt", fstream.Length.ToString());
            while (true)
            {
                //开辟缓冲区空间
                byte[] buffer = new byte[1024];
                //读取文件的数据
                int leng = fstream.Read(buffer, 0, 1024);
                //到文件结尾结束
                if (leng == 0)
                    break;
                //读出的文件数据长度等于缓冲区长度，直接将缓冲区数据写入
                if (leng == 1024)
                    HttpContext.Current.Response.BinaryWrite(buffer);
                else
                {
                    //读出文件数据比缓冲区小，重新定义缓冲区大小，只用于读取文件的最后一个数据块
                    byte[] b = new byte[leng];
                    for (int i = 0; i < leng; i++)
                        b[i] = buffer[i];
                    HttpContext.Current.Response.BinaryWrite(b);
                }
            }
            //关闭下载文件
            fstream.Close();
            //结束文件下载
            HttpContext.Current.Response.End();
        }

        /// <summary>
        /// 下载文件
        /// </summary>
        /// <param name="_Path"></param>
        public static void DownloadFile(string _Path)
        {
            FileInfo DownloadFile = new FileInfo(_Path);
            HttpContext.Current.Response.Clear();
            HttpContext.Current.Response.ClearHeaders();
            HttpContext.Current.Response.Buffer = false;
            HttpContext.Current.Response.ContentType = "application/x-msdownlad";
            HttpContext.Current.Response.AppendHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(DownloadFile.FullName, System.Text.Encoding.UTF8));
            HttpContext.Current.Response.AppendHeader("Content-Length", DownloadFile.Length.ToString());
            HttpContext.Current.Response.WriteFile(DownloadFile.FullName);
            HttpContext.Current.Response.Flush();
            HttpContext.Current.Response.End();
        }

        /// <summary>
        /// 删除文件
        /// </summary>
        /// <param name="_Path"></param>
        /// <returns></returns>
        public static bool DeleteFile(string _Path)
        {
            //判断文件是否存在
            if (File.Exists(_Path))
            {
                try
                {
                    File.Delete(_Path);
                }
                catch (Exception)
                {
                    return false;
                }
                return true;
            }
            return false;
        }

        #endregion
    }
}