C # simple download of file code from the server

1. // download transmitfile
Protected void button#click (Object sender, eventargs E)
{
/*
Microsoft provides a new transmitfile method for the response object to solve the problem of using response. binarywrite
When a file with more than Mbit/s is downloaded, The aspnet_wp.exe process cannot be recycled.
The Code is as follows:
*/
Response. contenttype = "application/X-zip-compressed ";
Response. addheader ("content-disposition", "attachment?filename=z.zip ");
String filename = server. mappath ("download/z.zip ");
Response. transmitfile (filename );
}

Ii. // download writefile
Protected void button2_click (Object sender, eventargs E)
{
/*
Using system. IO;

*/
String filename = "asd.txt"; // file name saved by the client
String filepath = server. mappath ("download/aaa.txt"); // path

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 ();
}

Iii. // multipart download of writefile
Protected void button3_click (Object sender, eventargs E)
{
String filename = "aaa.txt"; // file name saved by the client
String filepath = server. mappath ("download/aaa.txt"); // path

System. Io. fileinfo = new system. Io. fileinfo (filepath );

If (fileinfo. exists = true)
{
Const long chunksize = 102400; // 100 k reads only 100 k each time, which can relieve the pressure on the server
Byte [] buffer = new byte [chunksize];

Response. Clear ();
System. Io. filestream istream = system. Io. file. openread (filepath );
Long datalengthtoread = istream. length; // obtain the total size of the downloaded file
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); // read size
Response. outputstream. Write (buffer, 0, lengthread );
Response. Flush ();
Datalengthtoread = datalengthtoread-lengthread;
}
Response. Close ();
}
}

Iv. // stream download
Protected void button4_click (Object sender, eventargs E)
{
String filename = "aaa.txt"; // file name saved by the client
String filepath = server. mappath ("download/aaa.txt"); // path

// Download an object in the form of a streaming
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 ";
// Notify the browser to download the file instead of opening it
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 ");
// 'File name
Webform. response. addheader ("content-disposition", "attachment;
Filename = '"+ system. Web. httputility. urlencode (filenamewhenuserdownload,
System. Text. encoding. utf8) + "'");
Webform. response. contenttype = "application/octet-stream ";
// 'File content
Webform. response. Write (filebody );//-----------
Webform. response. End ();
}

// The above code downloads a dynamically generated text file. If the file already exists in the server-side object path, you can use the following function:

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 ");
// File name
Webform. response. addheader ("content-disposition", "attachment;
Filename = '"+ system. Web. httputility. urlencode (filenamewhenuserdownload,
System. Text. encoding. utf8) + "'");
Webform. response. contenttype = "application/octet-stream ";
// File Content
Webform. response. Write (system. Io. file. REA} dallbytes (filepath ));//---------
Webform. response. End ();

}

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From: http://hi.baidu.com/einyboy/blog/item/915c2937d5f490cda3cc2ba7.html