如何在asp.net MVC中生成链接以下载文件？

public class DownloadController : Controller
{
    public ActionResult DownloadFile()
    {
        // 获取文件路径
        string filePath = Server.MapPath("~/App_Data/file.txt");

        // 读取文件内容
        byte[] fileBytes = System.IO.File.ReadAllBytes(filePath);

        // 设置响应头
        Response.Clear();
        Response.ContentType = "application/octet-stream";
        Response.AddHeader("Content-Disposition", "attachment; filename=file.txt");
        Response.AddHeader("Content-Length", fileBytes.Length.ToString());

        // 将文件内容写入响应流
        Response.BinaryWrite(fileBytes);
        Response.End();

        return null;
    }
}

<a href="@Url.Action("DownloadFile", "Download")">点击下载文件</a>