ISerialized .Net, C#, Scrum and agile software development

The is keyword: Yet another hidden treasure of C#

A while back i blogged about the yield keyword and called it a hidden treasure of C# as I seldom see it used, and many senior developers never use it! Today, I came across a similar one,  namely the is-keyword. And frankly, I had actually forgotten about myself, even though I have used it in the past on several occasions.

Say, I want to check if a class is of a certain type, I could do it in the following way:

if (myClass.GetType().Equals(typeof(AnotherClass)))
{
    //do something
}

It works fine, but I wouldn't call it "Clean Code", and is not very readable! As a developer it is very easy to end up with this code, because we think: "OK, I have to check if myClass is of a ceratin type, then I need to get its type and compare it to AnotherClass, but to find the type of AnotherClass I have to use the typeof functionality".

Back when I programmed Java I used the instanceof keyword, and this was actually how I rediscovered the is-keyword of C#. The same code segment as above, but using the is-keysword looks far more readable:

if (myClass is MyClass)
{
    //do something
}

Even though the expression is not evaluated until run-time, you will get a compile-time warning if the expression is know to always be true or false, eg:

var myClass = new Int32();
if (myClass is Int32)
{
    //do something
}

Even though it's a very obvious example, it demonstrates the compile time evaluation! The compiler shows me the following message:

The given expression is always of the provided ('int') type

Strive for clean code, and use is rather than GetType() whenever possible!

About Paul Eie

My name is Pål Eie (English alias: Paul Eie) I'm an IT consultant working in Stavanger, Norway. My experience spans from AIX to Windows and from embedded C to Uniface, Java, C++ and C#. My blog will involve everything that is related to technology. As long as it might be of interest to either newbies or seniors, I will blog about it! If you find some of my posts about basic old technology, it just means you know more than many of my other readers!