求可用的 .net 下载文件代码

Question

怎么我这样下载下来的文件,如果稍大了点就报:!  不可预料的压缩文件末端(如果是rar),如果是dll文件下载下来通过文件对比却是不相同的如调用: downfile("http://127.0.0.1/aa.rar","c:\\aa.rar");        public bool downfile(string url, string LocalPath)
        {
            try
            {
                Uri u = new Uri(url);
                HttpWebRequest mRequest = (HttpWebRequest)WebRequest.Create(u);
                mRequest.Method = "GET";
                mRequest.ContentType = "application/x-www-form-urlencoded";                HttpWebResponse wr = (HttpWebResponse)mRequest.GetResponse();                Stream sIn = wr.GetResponseStream();
                FileStream fs = new FileStream(LocalPath, FileMode.Create, FileAccess.Write);                long length = wr.ContentLength;
                long i = 0;
                decimal j = 0;                while (i < length)
                {
                    byte[] buffer = new byte[1024];
                    i += sIn.Read(buffer, 0, buffer.Length);
                    fs.Write(buffer, 0, buffer.Length);                    if ((i % 1024) == 0)
                    {
                        j = Math.Round(Convert.ToDecimal((Convert.ToDouble(i) / Convert.ToDouble(length)) * 100), 4);                                                this.Invoke(new Function(delegate()
                        {
                            statusBar1.Text = "当前下载文件大小:" + length.ToString() + "字节   当前下载大小:" + i + "字节 下载进度" + j.ToString() + "%";
                        }));                        //statusBar1.Text = "当前下载文件大小:" + length.ToString() + "字节   当前下载大小:" + i + "字节 下载进度" + j.ToString() + "%";
                    }
                    else
                    {
                        this.Invoke(new Function(delegate()
                        {
                            statusBar1.Text = "当前下载文件大小:" + length.ToString() + "字节   当前下载大小:" + i + "字节";
                        }));
                        
                    }
                }                sIn.Close();
                wr.Close();
                fs.Close();
                MessageBox.Show("下载完成");
                return true;
            }
            catch(Exception err)
            {
                MessageBox.Show("下载失败:\n"+err.Message);
                return false;
            }        }

Answer 1

http://topic.csdn.net/t/20021104/21/1148279.html

Answer 2

 protected void Page_Load(object sender, EventArgs e)
    {
        DownloadFile("DownLoad\\aa.rar");
    }    /**/
    /// <summary>
    /// 下载文件
    /// </summary>
    /// <param name="filename">文件物理地址</param>
    protected void DownloadFile(string filename)
    {
        string saveFileName = "test.xls";
        int intStart = filename.LastIndexOf("\\") + 1;
        saveFileName = filename.Substring(intStart, filename.Length - intStart);
        System.IO.FileInfo fi = new System.IO.FileInfo(filename);
        string fileextname = fi.Extension;
        string DEFAULT_CONTENT_TYPE = "application/unknown";
        RegistryKey regkey, fileextkey;
        string filecontenttype;
        try
        {
            regkey = Registry.ClassesRoot;
            fileextkey = regkey.OpenSubKey(fileextname);
            filecontenttype = fileextkey.GetValue("Content Type", DEFAULT_CONTENT_TYPE).ToString();
        }
        catch
        {
            filecontenttype = DEFAULT_CONTENT_TYPE;
        }
        Response.Clear();
        Response.Charset = "utf-8";
        Response.Buffer = true;
        this.EnableViewState = false;
        Response.ContentEncoding = System.Text.Encoding.UTF8;
        Response.AppendHeader("Content-Disposition", "attachment;filename=" + saveFileName);
        Response.ContentType = filecontenttype;
        Response.WriteFile(filename);
        Response.Flush();
        Response.Close();
        Response.End();
    }
    //TransmitFile实现下载rar文件
    protected void Button1_Click(object sender, EventArgs e)
    {
        /*
         微软为Response对象提供了一个新的方法TransmitFile来解决使用Response.BinaryWrite
         下载超过400mb的文件时导致Aspnet_wp.exe进程回收而无法成功下载的问题。
         代码如下：
         */
        Response.ContentType = "application/x-zip-compressed";
        Response.AddHeader("Content-Disposition", "attachment;filename=z.zip");
        string filename = Server.MapPath("DownLoad/aa.rar");
        Response.TransmitFile(filename);
    }
    //WriteFile实现下载
    protected void Button2_Click(object sender, EventArgs e)
    {
        /*
      using System.IO;
        
      */        string fileName = "asd.txt";//客户端保存的文件名
        string filePath = Server.MapPath("DownLoad/huishouzhan.txt");//路径        FileInfo fileInfo = new FileInfo(filePath);
        Response.Clear();
        Response.ClearContent();
        Response.ClearHeaders();
        Response.AddHeader("Content-Disposition", "attachment;filename=" + fileName);
        Response.AddHeader("Content-Length", fileInfo.Length.ToString());
        Response.AddHeader("Content-Transfer-Encoding", "binary");
        Response.ContentType = "application/octet-stream";
        Response.ContentEncoding = System.Text.Encoding.GetEncoding("gb2312");
        Response.WriteFile(fileInfo.FullName);
        Response.Flush();
        Response.End();
    }
    //WriteFile分块下载
    protected void Button3_Click(object sender, EventArgs e)
    {
        string fileName = "aaa.txt";//客户端保存的文件名
        string filePath = Server.MapPath("DownLoad/huishouzhan.txt");//路径        System.IO.FileInfo fileInfo = new System.IO.FileInfo(filePath);        if (fileInfo.Exists == true)
        {
            const long ChunkSize = 102400;//100K 每次读取文件，只读取100Ｋ，这样可以缓解服务器的压力
            byte[] buffer = new byte[ChunkSize];            Response.Clear();
            System.IO.FileStream iStream = System.IO.File.OpenRead(filePath);
            long dataLengthToRead = iStream.Length;//获取下载的文件总大小
            Response.ContentType = "application/octet-stream";
            Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(fileName));
            while (dataLengthToRead > 0 && Response.IsClientConnected)
            {
                int lengthRead = iStream.Read(buffer, 0, Convert.ToInt32(ChunkSize));//读取的大小
                Response.OutputStream.Write(buffer, 0, lengthRead);
                Response.Flush();
                dataLengthToRead = dataLengthToRead - lengthRead;
            }
            Response.Close();
        }
    }
    /// <summary>
    /// 流方式下载
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void Button4_Click(object sender, EventArgs e)
    {
        string fileName = "aaa.txt";//客户端保存的文件名
        string filePath = Server.MapPath("DownLoad/huishouzhan.txt");//路径        //以字符流的形式下载文件
        FileStream fs = new FileStream(filePath, FileMode.Open);
        byte[] bytes = new byte[(int)fs.Length];
        fs.Read(bytes, 0, bytes.Length);
        fs.Close();
        Response.ContentType = "application/octet-stream";
        //通知浏览器下载文件而不是打开
        Response.AddHeader("Content-Disposition", "attachment;  filename=" + HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8));
        Response.BinaryWrite(bytes);
        Response.Flush();
        Response.End();
    }

Answer 3

LZ，你的代码里有地方写错了，所以会不正确，我改了一下你再拿去试试        public bool downfile(string url, string LocalPath)
        {
            try
            {
                Uri u = new Uri(url);
                HttpWebRequest mRequest = (HttpWebRequest)WebRequest.Create(u);
                mRequest.Method = "GET";
                mRequest.ContentType = "application/x-www-form-urlencoded";                HttpWebResponse wr = (HttpWebResponse)mRequest.GetResponse();                Stream sIn = wr.GetResponseStream();
                FileStream fs = new FileStream(LocalPath, FileMode.Create, FileAccess.Write);                long length = wr.ContentLength;
                long i = 0;
                int clen = 0;
                decimal j = 0;                while (i < length)
                {
                    byte[] buffer = new byte[1024];
                    clen = sIn.Read(buffer, 0, buffer.Length);
                    i += clen;
                    fs.Write(buffer, 0, clen);                    if ((i % 1024) == 0)
                    {
                        j = Math.Round(Convert.ToDecimal((Convert.ToDouble(i) / Convert.ToDouble(length)) * 100), 4);                                                this.Invoke(new Function(delegate()
                        {
                            statusBar1.Text = "当前下载文件大小:" + length.ToString() + "字节   当前下载大小:" + i + "字节 下载进度" + j.ToString() + "%";
                        }));                        //statusBar1.Text = "当前下载文件大小:" + length.ToString() + "字节   当前下载大小:" + i + "字节 下载进度" + j.ToString() + "%";
                    }
                    else
                    {
                        this.Invoke(new Function(delegate()
                        {
                            statusBar1.Text = "当前下载文件大小:" + length.ToString() + "字节   当前下载大小:" + i + "字节";
                        }));
                        
                    }
                }                sIn.Close();
                wr.Close();
                fs.Close();
                MessageBox.Show("下载完成");
                return true;
            }
            catch(Exception err)
            {
                MessageBox.Show("下载失败:\n"+err.Message);
                return false;
            }        }