How to generate an iCalendar file (ASP.NET/C#)

It is fairly simple to generate an iCalendar file (for calendar clients like Microsoft Outlook or Mozilla Sunbird) as it is just a plain text file with the extension 'ics'. A WebHandler is the best method of doing this.

Update (10 Feb 2006): Now works in Sunbird. When prompted to open / save the file, choose to download. Then in Sunbird, go to File > Import and browse for the saved file.

iCalendar.ashx

<%@ WebHandler Language="C#" Class="MyNamespace.iCalendar" %>
using System;
using System.Web;
namespace MyNamespace
{
 public class iCalendar: IHttpHandler 
 {
  
  public bool IsReusable
  {
   get
   {
    return true;
   }
  }

  string DateFormat
  {
    get
    {
      return "yyyyMMddTHHmmssZ"; // 20060215T092000Z
    }
  }
  
  
  public void ProcessRequest(HttpContext ctx)
  {
   DateTime startDate = DateTime.Now.AddDays(5);
   DateTime endDate = startDate.AddMinutes(35);
   string organizer = "foo@bar.com";
   string location = "My House";
   string summary = "My Event";
   string description = "Please come to\\nMy House";
   
   ctx.Response.ContentType="text/calendar";
   ctx.Response.AddHeader("Content-disposition", "attachment; filename=appointment.ics");
   
   ctx.Response.Write("BEGIN:VCALENDAR");
   ctx.Response.Write("\nVERSION:2.0");
   ctx.Response.Write("\nMETHOD:PUBLISH");
   ctx.Response.Write("\nBEGIN:VEVENT");
   ctx.Response.Write("\nORGANIZER:MAILTO:" + organizer);
   ctx.Response.Write("\nDTSTART:" + startDate.ToUniversalTime().ToString(DateFormat));
   ctx.Response.Write("\nDTEND:" + endDate.ToUniversalTime().ToString(DateFormat));
   ctx.Response.Write("\nLOCATION:" + location);
   ctx.Response.Write("\nUID:" + DateTime.Now.ToUniversalTime().ToString(DateFormat) + "@mysite.com");
   ctx.Response.Write("\nDTSTAMP:" + DateTime.Now.ToUniversalTime().ToString(DateFormat));
   ctx.Response.Write("\nSUMMARY:" + summary);
   ctx.Response.Write("\nDESCRIPTION:" + description);
   ctx.Response.Write("\nPRIORITY:5");
   ctx.Response.Write("\nCLASS:PUBLIC");
   ctx.Response.Write("\nEND:VEVENT");
   ctx.Response.Write("\nEND:VCALENDAR");
   ctx.Response.End();
  }
 }
}

Comments

Mr. T said…
simple, straightforward, keepin it simple, stupid... props.
8:31 pm, April 28, 2009
Eric Barr said…
I don't doubt that a Web Handler is the best way to do this, since I read that it saves overhead from the typical page class. But if you're not worried about the performance (I'm not) then I found that you can just put this code in the Page_Load of a typical .aspx page and remove the "ctx." on each line and it works that way too! Thanks for the post, it helped a lot!
11:38 pm, July 10, 2009
Post a Comment

Popular posts from this blog

Select box manipulation with jQuery

If you read the jQuery mailing list , you may be aware that I have updated my plugins for working with select boxes . Summary of changes: addOption replaces any options with the same value (so think of it as an add/replace options plugin selectOptions selected options in addition to what was already selected, but there is now an option for it not to do this There are two new methods: copyOptions which is for copying options between select boxes ajaxAddOption allows you to add options via AJAX (i.e. could be used for create options dynamically from a server script)
Read more

iTextSharp: Generating a Basic PDF file (ASP.NET/C#)

iTextSharp is free library for .NET that allows you to create PDF documents. It can be used to dynamically create PDF's which can be streamed to the user. As there is no HTML being sent to the user, a WebHandler (ashx file) is a more appropriate way to generate your PDF than an aspx page. Download itextsharp-3.0.10-dll.zip (latest version as of 08 Feb 2006) and save the dll in the archive to your websites bin directory. Here is a basic sample of creating a PDF (more complex samples may follow in future posts). BasicPDF.ashx <%@ WebHandler Language="C#" Class="MyNamespace.BasicPDF" %> using System; using System.IO; using System.Web; using iTextSharp.text; using iTextSharp.text.pdf; namespace MyNamespace { public class BasicPDF: IHttpHandler { public bool IsReusable { get { return true; } } /// <summary> /// Font used for any hyperlinks added to the PDF /// </summary> private Font LinkFont { get ...
Read more

Popup Window Countdown (JavaScript)

This code opens a new popup window that contains a timer that counts down, then closes the window when it reaches 0. Will not work if user has a popup blocker blocking the page. <html> <head> <title>Popup Timer</title> <script language="JavaScript" type="text/JavaScript"> // popup window var var popup; // At what number shall the countdown counter start? CounterStart = 10; // This function CustomAction() can be modified to do // whatever you want done every second. function CustomAction() { popup.document.timer.timeleft.value = CounterStart; } // end of function CustomAction() // end of JavaScript customization function Decrement() { CounterStart--; CustomAction(); if(CounterStart <= 0) { popup.close(); alert('Timer reached 0'); } else { setTimeout('Decrement()',1000); } } function StartTheCounter() { openPopup(120,100); setTimeout('Decrement()',1000); } f...
Read more