如何在asp.net中实现文件下载

using System;
using System.IO;
using System.Web;

public partial class Download : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        string filePath = Server.MapPath("~/Files/example.txt"); // 替换为要下载的文件的路径
        string fileName = "example.txt"; // 替换为要下载的文件的名称

        if (File.Exists(filePath))
        {
            Response.Clear();
            Response.ContentType = "application/octet-stream";
            Response.AddHeader("Content-Disposition", "attachment; filename=" + fileName);
            Response.AddHeader("Content-Length", filePath.Length.ToString());
            Response.WriteFile(filePath);
            Response.End();
        }
        else
        {
            Response.Write("文件不存在。");
        }
    }
}