asp.net 文件下载(转)

public partial class WebDownloadFile : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
string id = Request.QueryString["ID"].ToString();
DownloadFile d = new DownloadFile(id);
if (File.Exists(d.FullPath))
{
Download2(d.FullPath, d.FileName);
}
else
{
Response.Write("文件不存在，请联系管理员！");
}
}
}
/// <summary>
/// 下载文件
/// </summary>
/// <param name="FullPath">文件全路径</param>
/// <param name="FileName">客户端下载名称</param>
protected void Download1(string FullPath, string FileName)
{
/*
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/octet-stream";
Response.AddHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(FileName) + "");
Response.TransmitFile(FullPath);
}

//WriteFile实现下载
/// <summary>
/// 下载文件
/// </summary>
/// <param name="FullPath">文件全路径</param>
/// <param name="FileName">客户端下载名称</param>
protected void Download2(string FullPath, string FileName)
{
FileInfo fileInfo = new FileInfo(FullPath);
Response.Clear();
Response.ClearContent();
Response.ClearHeaders();
Response.AddHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(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
/// <summary>
/// 下载文件
/// </summary>
/// <param name="FullPath">文件全路径</param>
/// <param name="FileName">客户端下载名称</param>
protected void Download3(string FullPath, string FileName)
{

System.IO.FileInfo fileInfo = new System.IO.FileInfo(FullPath);

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(FullPath);
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();
}
}

//流方式下载
/// <summary>
/// 下载文件
/// </summary>
/// <param name="FullPath">文件全路径</param>
/// <param name="FileName">客户端下载名称</param>
protected void Download4(string FullPath, string FileName)
{

1. //以字符流的形式下载文件

FileStream fs = new FileStream(FullPath, 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));
Response.BinaryWrite(bytes);
Response.Flush();
Response.End();

}
}