Response.AddHeader "content-disposition","attachment; filename=fname.ext"

public static void ToDownload(string serverfilpath,string filename)

{

FileStream fileStream = new FileStream(serverfilpath, FileMode.Open);

long fileSize = fileStream.Length;
HttpContext.Current.Response.ContentType = "application/octet-stream";
HttpContext.Current.Response.AddHeader("Content-Disposition", "attachment; filename=\"" + UTF_FileName(filename) + "\";");
////attachment --- 作为附件下载
////inline --- 在线打开

HttpContext.Current.Response.AddHeader("Content-Length", fileSize.ToString());
byte[] fileBuffer = new byte[fileSize];
fileStream.Read(fileBuffer, 0, (int)fileSize);

HttpContext.Current.Response.BinaryWrite(fileBuffer);

fileStream.Close();

HttpContext.Current.Response.End();

}



public static void ToOpen(string serverfilpath, string filename)

{

FileStream fileStream = new FileStream(serverfilpath, FileMode.Open);

long fileSize = fileStream.Length;
HttpContext.Current.Response.ContentType = "application/octet-stream";
HttpContext.Current.Response.AddHeader("Content-Disposition", "inline; filename=\"" + UTF_FileName(filename) + "\";");
HttpContext.Current.Response.AddHeader("Content-Length", fileSize.ToString());

byte[] fileBuffer = new byte[fileSize];
fileStream.Read(fileBuffer, 0, (int)fileSize);
HttpContext.Current.Response.BinaryWrite(fileBuffer);
fileStream.Close();

HttpContext.Current.Response.End();

}



private static string UTF_FileName(string filename)

{

return HttpUtility.UrlEncode(filename, System.Text.Encoding.UTF8);

}