Covariance and Contravariance in C# 4.0

Over the last couple of days I have read a number of blogs on the topic of covariance and contravariance, a new feature to be introduced in the upcoming C# 4.0 release. Whilst most of the blog posts were happy to provide a detailed account of what these terms…

Converting Hex string to Int in C#

For a hex literal that’s not prefixed you can quite easily convert it using int.Parse in C#:

[code lang=”csharp”]
string hex = “142CBD”;
// this returns 1322173
int intValue = int.Parse(hex, System.Globalization.NumberStyles.HexNumber);
[/code]

Pattern for dealing with null handler for events in C#

If you’ve used events in C# before, you’ve probably written code like this too:

[code lang=”csharp”]
public event EventHandler Started;
…
// make sure Started is not null before firing the event
// else…

LINQ — Lambda Expression vs Query Expression

As you’re probably aware of already, LINQ comes in two flavours — using Lambda expressions and using SQL-like query expressions:

[code lang=”csharp”]
Func<int, bool> isEven = i => i % 2 == 0;
int[] ints = new int[] { 1, 2, 3…

LINQ — choosing between Concat() and Union()

In Linq To Objects, there are two ways you can join two sequences together, using either Concat() or Union(), and as I was wondering how the two differs I came across this post:

Threading — Using ReaderWriterLockSlim

When dealing with concurrency/threading issues in .Net, the normal approach is to use lock() to lock a dedicated sync object like this:

[code lang=”csharp”]
private static readonly object padlock = new object();
…
lock(padlock)
{
 //…

Buzzword Buster — Stylesheets, XSL and XSLT

Stylesheet

A Stylesheet language or style language, is a computer language used to describe the presentation of structured documents. A structured document which doesn’t break the schema it is designed to conform to is…

Buzzword Buster — DDD

Definition:

Domain Driven Design (DDD) is an approach to software design which puts the focus on the problem domain and provides a structure for making design decisions to accelerates software development for complicated domains. The key components in DDD…