public void DownFile(string filePath ,string fileName )
{
 // filePath 文件路徑 例如：/File/記錄.xlsx 
 // fileName 文件名稱 例如：記錄.xlsx （要后綴哦）
Encoding encoding; // 申明編碼
string outputFileName; // 輸出名字
Debug.Assert(HttpContext.ApplicationInstance.Request.UserAgent != null, "HttpContext.ApplicationInstance.Request.UserAgent != null");
string browser = HttpContext.ApplicationInstance.Request.UserAgent.ToUpper();
// 微軟的瀏覽器和ie過濾
if (browser.Contains("MS") && browser.Contains("IE"))
{
outputFileName = HttpUtility.UrlEncode(filePath);
encoding = Encoding.Default;
}
//火狐
else if (browser.Contains("FIREFOX"))
{
outputFileName = fileName;
encoding = Encoding.GetEncoding("GB2312");
}
else
{
outputFileName = HttpUtility.UrlEncode(fileName);
encoding = Encoding.Default;
}
string absoluFilePath = Server.MapPath(filePath); //獲取上傳文件路徑
FileStream fs = new FileStream(absoluFilePath, FileMode.Open);
byte[] bytes = new byte[(int)fs.Length];
fs.Read(bytes, 0, bytes.Length);
fs.Close(); //關(guān)閉流，釋放資源
HttpContext.ApplicationInstance.Response.Clear();
HttpContext.ApplicationInstance.Response.Buffer = true;
HttpContext.ApplicationInstance.Response.ContentEncoding = encoding;
HttpContext.ApplicationInstance.Response.AddHeader("Content-Disposition", string.Format("attachment; filename={0}", string.IsNullOrEmpty(outputFileName) ? DateTime.Now.ToString("yyyyMMddHHmmssfff") : outputFileName));
Response.BinaryWrite(bytes);
Response.Flush();
HttpContext.ApplicationInstance.Response.End();
}