Tuesday, 21 February 2012

What are Generics in .NET?

A little while ago, a friend of mine on Facebook asked me to explain to him what generics in .NET were. As I thought this might interest more than one friend, which it did, I decided to put it in a "note" on Facebook. That was before I started this blog, so now I decided to post it here, hopefully so that more people would find it useful.

Generics in the .NET Framework is a programming technique that allows you to create a "generic" (meaning that it's not tied to a specific type) class, structure or method. The type, which is in this case "an argument", is specified when that element is used. What's interesting, and this is another advantage of Generics in .NET, is that you can restrict that type by specifying, for example, that it has to implement a certain interface or have a parameterless constructor.

This concept allows for more type safety (the type is known when the generic element is being used), while promoting reuse (you create an element that's not tied to a specific type).

An example of Generics, which is very popular, are Generic Collections, that came with the introduction of Generics in .NET 2.0. In the earlier version of .NET (1.x), there were non-generic collections, meaning that those collections would hold "Object" types, allowing the following:

ArrayList collection = new ArrayList();
collection.Add(new float[10]);

This may seem to have the advantage to be "flexible" but it has many disadvantages, like having to cast the types back when retrieving them:

int i= (int) collection[1];

And you have to know which element contains which type, and that can prove to be hard. Also, cases when you would need such a collection that can hold any "Object" aren't that common.
And here come the "Generics" to the rescue. You can use, for example, the List<T> to hold objects of type "T". e.g:

List<string> stringList = new List<string>();
stringList.Add(2); // this causes a compile-time error
string world = stringList[1]; // no need for the cast since the type is known

Another example of generics, other than in collections, would be something like:

int Compare<T>(T first, T second) where T:IComparable<T>
return first.CompareTo(second);

Now, this Compare method can compare any two objects (of the same type) which implement the IComparable interface (that defines the CompareTo method), which in turn makes for another good example of generics

public interface IComparable<T>
int CompareTo(T other);

Now, if you've not used generics before, maybe thinking they were hard, I hope you got a glimpse at how powerful this feature is and how useful it can be; and more importantly, how "not so hard after all" it is. So, what are you still doing here?! go make yourself some generics ;)


  1. I came onto your blog while focusing just slightly submits. Nice strategy for next, I will be bookmarking at once seize your complete rises... SEO company

  2. One of the most appealing and bewitching blog that I read recently.
    augmented reality advertising

  3. This allows them to go to class prepared. They also like using Skype, emailing their teachers instead of going to speak to them in person. They also enjoy discussion boards. wolffofcanada.com

  4. This blog has irresistibly pleased its audience.
    jio fi

  5. The author has done a fine job of converting the feelings into words.
    best noise cancelling headphones under 100

  6. The blog writings were so nice, I wished they neever ended.

  7. The return on investment will depend on whether the technologies implemented are right for a given business' needs and how prepared employees are to use them.lie detector test uk

  8. To be able to keep yourself up to date you must come across some reliable latest technology news sources that can give you timely information

  9. I’ve been exploring for a little for any high-quality articles or weblog posts on this kind of area . Exploring in Yahoo I finally stumbled upon this web site. Reading this information So i’m glad to express that I’ve an incredibly good uncanny feeling I discovered just what I needed. I most no doubt will make sure to don’t forget this website and give it a glance regularly. APK

  10. This is highly informatics, crisp and clear. I think that everything has been described in systematic manner so that reader could get maximum information and learn many things.

  11. Hello, i think that i saw you visited my site so i came to “return the favor”.I am attempting to find things to enhance my site!I suppose its ok to use a few of your ideas!! stadtbedarf.de

  12. The very best drones can also have some of the people top-of-the-line energy digital cameras on board as well as pass on the pictures right to rescuers using a Very first Individual Look at system.videos by a camera drone

  13. AWS Training in Bangalore - Live Online & Classroom
    myTectra Amazon Web Services (AWS) certification training helps you to gain real time hands on experience on AWS. myTectra offers AWS training in Bangalore using classroom and AWS Online Training globally. AWS Training at myTectra delivered by the experienced professional who has atleast 4 years of relavent AWS experince and overall 8-15 years of IT experience. myTectra Offers AWS Training since 2013 and retained the positions of Top AWS Training Company in Bangalore and India.

    IOT Training in Bangalore - Live Online & Classroom
    IOT Training course observes iot as the platform for networking of different devices on the internet and their inter related communication. Reading data through the sensors and processing it with applications sitting in the cloud and thereafter passing the processed data to generate different kind of output is the motive of the complete curricula. Students are made to understand the type of input devices and communications among the devices in a wireless media.

  14. Such a movement would coordinate the subjects of technology, social investigations, math, science, and dialect expressions with the chance to make understudy focused action.top entrepreneur movies about sales