C# 从服务器下载文件代码 以excel为例

一、//TransmitFile实现下载
protectedvoid 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
protectedvoid 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
protectedvoid 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)
{
constlong 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
protectedvoid 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();
}

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

publicvoid 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：

publicvoid 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();

｝ 一、//TransmitFile实现下载
protectedvoid 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
protectedvoid 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
protectedvoid 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)
{
constlong 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 =newbyte[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
protectedvoid 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=newbyte[(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();
}

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

publicvoid 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：

publicvoid 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();

｝