文件下載方式大全（瀏覽器）

1.在asp.net中，有很多類似DataList的數據控件，通過以下代碼，可以將這個數據控件中的數據保存為指定格式的文件，例如Excel，xml等
System.IO.StringWriter tw = new System.IO.StringWriter();
System.Web.UI.HtmlTextWriter hw = new System.Web.UI.HtmlTextWriter(tw, @"");
Response.AddHeader("content-disposition", "attachment; filename=result.xml");
// Response.ContentType = "application/vnd.ms-excel";
Response.ContentType = "application/vnd.ms-xml";
Response.Charset = "utf-8";
DataSet ds = new SqlHelp().ExcSQL("select * from quan", CommandType.Text);
DataList1.DataSource = ds;
DataList1.DataBind();
DataList1.RenderControl(hw);
Response.Write(tw.ToString());
Response.End();

//TransmitFile实现下载
protected void Button1_Click1(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：
*/
string strFileName = "三部闲置设备管理系统操作手册IEMS.ppt";
Response.ContentType = "application/x-zip-compressed";
//Response.ContentEncoding = System.Text.Encoding.GetEncoding("gb2312");
string filename = BLL.Config.PART_EM_UPLOAD_DOC + strFileName;
//BLL.Config.PART_EM_UPLOAD_DOC 为路径 ("D:/EMUploadDoc/")
Response.AddHeader("Content-Disposition", "attachment;filename=" +Server.UrlPathEncode(strFileName));
//Server.UrlPathEncode()解决文件名的乱码问题.

Response.TransmitFile(filename);
}

//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();
}

//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();
}
}

//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();
}