Skip to main content Handler For Writing and Downloading Binary

An ASP.NET HTTP handler is the process (frequently referred to as the "endpoint") that runs in response to a request made to an ASP.NET Web application. The most common handler is an ASP.NET page handler that processes .aspx files. When users request an .aspx file, the request is processed by the page through the page handler. You can create your own HTTP handlers that render custom output to the browser.

The HttpHandler is a pre-processing logic implementation blocks and is the part of the ASP.NET request pipeline. Whenever the IIS Server recieves a request, it looks for an ISAPI filter(looking for the perticuler httphandler to handle a perticuler extension) that is capable of handling web requests.

ASP.NET maps HTTP requests to HttpHandlers. Each HttpHandler enables processing of individual HTTP URLs or groups of URL extensions within an application.

Handlers are considered to be more lightweight object than pages. That's why they are used to serve dynamically-generated images, on-the-fly generated PDF-files and similar content to the web browser.

below is an example (.ashx file)..

<%@ WebHandler Language="C#" Class="DownLoad" %>
using System;
using System.Web;
using System.Data;
using System.Data.SqlClient;

public class DownLoad : IHttpHandler {

  CompCls ObjComp = new CompCls();
  public void ProcessRequest(HttpContext context)
     string conString = ObjComp.strCon;
     SqlConnection con = new SqlConnection(conString);
     string Proj = context.Request["id"];
     SqlDataAdapter Ad = new SqlDataAdapter("SELECT   Attachment,AttachmentFileName FROM tblProjectsAttachment WHERE EntryId=@EntryId", con);
    Ad.SelectCommand.Parameters.AddWithValue("@EntryId", Proj);
    DataSet DS = new DataSet();

    using (con)
        byte[] file = (byte[])DS.Tables[0].Rows[0][0];
        string Filename = DS.Tables[0].Rows[0][1].ToString();
            ("Content-Disposition","inline;attachment; filename=\"" + Filename + "\"");
             context.Response.AddHeader("Content-Length", file.Length.ToString());
             context.Response.ContentType = "application/octet-stream";
        catch (Exception ex)
            context.Response.ContentType = "text/plain";


 public bool IsReusable {
    get {
        return false;

Want to more about http handler and http module go to below link (httphandler and httpmodule in

If We are hosting your application in IIS 7 then you have to do some additional setting in IIS 7 to be register httphandler and httpmodule in IIS 7 take look at this link below. httpmodules-and-httphandlers-in-iis-7.html

Popular posts from this blog

how $document.ready() is different from window.onload()

we often use window.onload() in javascript and $document.ready() in jquery and assume that both are same just jquery library wrap up javascript window.onload() and introduce $document.ready() but no there is much difference between them below is the explanation -

regex - check if a string contains only alphabets c#

How to validate that input string contains only alphabets, validating that textbox contains only alphabets (letter), so here is some of the ways for doing such task. char have a property named isLetter which is for checking if character is a letter or not, or you can check by the regular expression  or you can validate your textbox through regular expression validator in Following code demonstrating the various ways of implementation.

Merging multiple PDFs using iTextSharp in c#

In this article i will show you how to merge multiple pdfs into one using ITextSharp below is the two approach one is to pass your input files path, output file path (will be created if not exist) and another is pass direct input stream, output stream and it will write the merge files into output stream.

How to handle click event of linkbutton inside gridview

Recently I have posted how to sort only current page of gridview , Scrollble gridview with fixed header through javascript , File upload control inside gridview during postback and now i am going to explain how to handle click event of linkbutton or any button type control inside gridview. We can handle click event of any button type control inside gridview by two way first is through event bubbling and second one is directly (in this type of event handling we need to access current girdviewrow container)