asp.net下载文件方法

/// <summary>
/// 下载
/// </summary>
/// <param name="url"></param>
/// <returns></returns>
public static bool DownLoadFile(string url)
{
var flag = false;
try
{
var filePath = HttpContext.Current.Server.MapPath(url); //获取文件的路径
var file = new FileInfo(filePath); //得到文件
if (file.Exists) //判断文件是否存在
{
HttpContext.Current.Response.Clear(); //清空Response对象
/*设置浏览器请求头信息*/
HttpContext.Current.Response.AddHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(file.Name)); //指定文件
HttpContext.Current.Response.AddHeader("Content-Length", file.Length.ToString()); //指定文件大小
HttpContext.Current.Response.ContentType = "application/application/octet-stream"; //指定输出方式
HttpContext.Current.Response.WriteFile(file.FullName); //写出文件
HttpContext.Current.Response.End(); //结束Response对象
HttpContext.Current.Response.Flush(); //输出缓冲区(刷新Response对象)
HttpContext.Current.Response.Clear(); //清空Response对象

flag = true;
}
else
{
flag = false;
}
}
catch (Exception)
{
flag = false;
}
return flag;
}