ASHX handler in Asp.Net

An ASHX handler allows you a discrete http handler without the overhead of processing a page request (an ASPX file).

<%@ WebHandler Language="C#" Class="Handler" %>

using System;
using System.Web;

public class Handler : IHttpHandler {
   
    public void ProcessRequest (HttpContext context) {
        var fileName = "must.sql";
        var r = context.Response;
        r.AddHeader("Content-Disposition", "attachment; filename=" + fileName);
        r.ContentType = "text/plain";
        r.WriteFile(context.Server.MapPath(fileName));

    }
 
    public bool IsReusable {
        get {
            return false;
        }
    }

}

 Now, You have to create button in your .aspx page write the code as following

<asp:Button ID="Button1" runat="server" onclick="Button1_Click" Text="Button" />

protected void Button1_Click(object sender, EventArgs e)
    {
        Response.Redirect("Handler.ashx");
    }