string fileURL = this.Server.MapPath("你要下載的文件路徑")

;//文件路徑，可用相對路徑FileInfo fileInfo = new FileInfo(fileURL)

;Response.Clear()

;Response.AddHeader("content-disposition", "attachment;filename=" + Server.UrlEncode(fileInfo.Name.ToString()))

;//文件名Response.AddHeader("content-length", fileInfo.Length.ToString())

;//文件大小Response.ContentType = "application/octet-stream"

;Response.ContentEncoding = System.Text.Encoding.Default;Response.WriteFile(fileURL);