C# download file from webserver

分手后的思念是犯贱 2022-08-27 11:55 201阅读 0赞

一、//TransmitFile实现下载  
    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/z.zip");  
        Response.TransmitFile(filename);  
    \}

二、//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/aaa.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();  
    \}

三、   //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/aaa.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();  
        \}  
    \}

四、//流方式下载  
    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/aaa.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();  
    \}

//----------------------------------------------------------

public void DownloadFile( System.Web.UI.Page WebForm,String FileNameWhenUserDownload ,String FileBody )  
\{

WebForm.Response.ClearHeaders();  
　　WebForm.Response.Clear();  
　　WebForm.Response.Expires = 0;  
　　WebForm.Response.Buffer = true;  
　　WebForm.Response.AddHeader("Accept-Language", "zh-tw");  
　　//'文件名称  
　　WebForm.Response.AddHeader("content-disposition", "attachment; filename='"+System.Web.HttpUtility.UrlEncode(FileNameWhenUserDownload, System.Text.Encoding.UTF8)+"'");  
　　WebForm.Response.ContentType = "Application/octet-stream";  
　　//'文件内容  
　　WebForm.Response.Write(FileBody);//-----------  
    WebForm.Response.End();  
\}

//上面这段代码是下载一个动态产生的文本文件，若这个文件已经存在于服务器端的实体路径，则可以通过下面的函数：

public void DownloadFileByFilePath( System.Web.UI.Page WebForm,String FileNameWhenUserDownload ,String FilePath )  
\{  
　　WebForm.Response.ClearHeaders();  
　　WebForm.Response.Clear();  
　　WebForm.Response.Expires = 0;  
    WebForm.Response.Buffer = true;  
　　WebForm.Response.AddHeader("Accept-Language", "zh-tw");  
　　//文件名称  
　　WebForm.Response.AddHeader("content-disposition", "attachment; filename='" + System.Web.HttpUtility.UrlEncode(FileNameWhenUserDownload, System.Text.Encoding.UTF8) +"'" );  
　　WebForm.Response.ContentType = "Application/octet-stream";  
　　//文件内容  
　　WebForm.Response.Write(System.IO.File.Rea\}dAllBytes(FilePath));//---------  
　　WebForm.Response.End();

｝

如果是winform,就要用下面的方法：

private void button1\_Click(object sender, EventArgs e)  
        \{  
            string url = "http://localhost:8080/your.rar";  
            DownloadFile(url,"yourddd.rar");  
        \}  
  
          
        private bool DownloadFile(string URL, string filename)  
        \{  
            try  
            \{  
                System.Net.HttpWebRequest Myrq = (System.Net.HttpWebRequest)System.Net.HttpWebRequest.Create(URL);  
                System.Net.HttpWebResponse myrp = (System.Net.HttpWebResponse)Myrq.GetResponse();  
                System.IO.Stream st = myrp.GetResponseStream();  
                System.IO.Stream so = new System.IO.FileStream(filename, System.IO.FileMode.Create);  
                byte\[\] by = new byte\[1024\];  
                int osize = st.Read(by, 0, (int)by.Length);  
                while (osize > 0)  
                \{  
                    so.Write(by, 0, osize);  
                    osize = st.Read(by, 0, (int)by.Length);  
                \}  
                so.Close();  
                st.Close();  
                myrp.Close();  
                Myrq.Abort();  
                return true;  
            \}  
            catch (System.Exception e)  
            \{  
                MessageBox.Show(e.Message);  
                return false;  
            \}  
        \}