效果：
思路：
简单的有两种方式下载，一种是流下载，一种是WriteFile下载。以下是使用WriteFile下载。
代码：
protected void LinkButton1_Click(object sender, EventArgs e)
{
try
{
//WriteFile实现下载(word)
string fileName = "qingpingguo.docx";//客户端保存的文件名
string filePath = Server.MapPath("~\excel\" + tb1.Text);//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();
}
catch (Exception ex)
{
Response.Write(ex.Message);
}
/*************以下为流方式下载****************/
//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();
}