download excel sheet/video/any thing from folder in the solution

// just writ this code under button click:

 protected void Button1_Click(object sender, EventArgs e)
    {
        string filename = "qtn.txt";//file name which used to download
        string filepath = "README.txt";//where you want to download the file
        Response.Clear();
        Response.AppendHeader("Content-Disposition", "attachment; filename=" + filename);
        Response.ContentType = "application//octet-stream";
        Response.TransmitFile(Server.MapPath(filepath));
        Response.End();
    }