asp.net实现下载

Shared Function DownloadFile(ByVal WebForm As System.Web.UI.Page, ByVal FileNameWhenUserDownload As String, ByVal FileBody As String)
　　WebForm.Response.ClearHeaders()
　　WebForm.Response.Clear()
　　WebForm.Response.Expires = 0
　　WebForm.Response.Buffer = True
　　WebForm.Response.AddHeader("Accept-Language", "zh-tw")
　　'文件名称
　　WebForm.Response.AddHeader("content-disposition", "attachment; filename=" & Chr(34) & System.Web.HttpUtility.UrlEncode(FileNameWhenUserDownload, System.Text.Encoding.UTF8) & Chr(34))
　　WebForm.Response.ContentType = "Application/octet-stream"
　　'文件内容
　　WebForm.Response.Write(FileBody)
　　WebForm.Response.End()
End Function

上面这段代码是下载一个动态产生的文本文件，若这个文件已经存在于服务器端的实体路径，则可以通过下面的函数：
Shared Sub DownloadFile(ByVal WebForm As System.Web.UI.Page, ByVal FileNameWhenUserDownload As String, ByVal FilePath As String)
　　WebForm.Response.ClearHeaders()
　　WebForm.Response.Clear()
　　WebForm.Response.Expires = 0
　　WebForm.Response.Buffer = True
　　WebForm.Response.AddHeader("Accept-Language", "zh-tw")
　　'文件名称
　　WebForm.Response.AddHeader("content-disposition", "attachment; filename=" & Chr(34) & System.Web.HttpUtility.UrlEncode(FileNameWhenUserDownload, System.Text.Encoding.UTF8) & Chr(34))
　　WebForm.Response.ContentType = "Application/octet-stream"
　　'文件内容
　　WebForm.Response.Write(System.IO.File.ReadAllBytes(FilePath))
　　WebForm.Response.End()
End Sub