Date Manipulation - GoToWeek and WeekOfYear (C#)

GoToWeek goes to the specific week in a year (e.g. GoToWeek(2006, 10) would go return the start day of week 10 in 2006 - 27th February). WeekOfYear returns the given dates Week Number (e.g. GoToWeek(DateTime.Now) would return 27). Uses the current threads culture, so will work with whatever culture you have set the current thread to (e.g. System.Threading.Thread.CurrentThread.CurrentCulture = new System.Globalization.CultureInfo("en-GB");).

private DateTime GoToWeek(int year, int week)
{
 // use the current culture
 System.Globalization.CultureInfo ci = System.Threading.Thread.CurrentThread.CurrentCulture;
 // get first day of week from culture
 DayOfWeek fdow = ci.DateTimeFormat.FirstDayOfWeek;
 
 // new empty Date (so starts 01/01/0001)
 DateTime d = new DateTime();
 
 // year starts at 1, so take away 1 from desired year to prevent going to the next one
 d = d.AddYears(year - 1);
 
 // get day January 1st falls on
 int startDay = (int)d.DayOfWeek;
 
 // get the difference between the first day of the week, and the day January 1st starts on
 int difference = (int)fdow - startDay;
 // if it is positive (i.e. after first day of week), take away 7
 if(difference > 0)
 {
  difference = difference - 7;
 }
 
 // already on week 1, so add desired number of weeks - 1 * days in week
 if(week > 1)
 {
  d = d.AddDays((week - 1) * 7 + difference);
 }
 
 return d;
}

private int WeekOfYear(DateTime date)
{
 // use the current culture
 System.Globalization.CultureInfo ci = System.Threading.Thread.CurrentThread.CurrentCulture;
 // use current culture's calendar
 System.Globalization.Calendar cal = ci.Calendar;
 // get the calendar week rule (i.e. what determines the first week in the year)
 System.Globalization.CalendarWeekRule cwr = ci.DateTimeFormat.CalendarWeekRule;
 // get the first day of week for the current culture
 DayOfWeek fdow = ci.DateTimeFormat.FirstDayOfWeek;
 // return the week
 return cal.GetWeekOfYear(date, cwr, fdow);
}

Tags: , , , ,

Comments

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