Basics Of Generic Classes In C#

Devesh Omar

7y229.2k21100Article

C#C# Generic ClassBasic of Generic ClassResolve the problem using Generics

21 Comments

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Dilshad Ashraf5y ago
Nice explanation...Thanks for sharing...
Md Hussain6y ago
Good explanation Thank you
Juan Priotti7y ago
Good one, thanks for sharing!
Ankur Mistry7y ago
Thanks for sharing...
Hemalatha Sunnapu7y ago
I want reply for my comment.........
Hemalatha Sunnapu7y ago
We can call a method with different data types by just declaring actually parameters as dynamic..............
Karthik Elumalai8y ago
Good and nicely explained
Rakesh reddy9y ago
Its very clear to understand about Generic classes. Thank you very munch
Hrishikesh Kulkarni9y ago
Thanks Nice Example
Devesh Omar9y ago
Another blog: http://compilefactory.blogspot.in/2017/03/basics-of-generic-classes-in-c.html
Hemant Bharadwaj10y ago
Well Explanined
Pravin Kale10y ago
Hi Devesh Omar, we can do same thing using following code .can you please explain use of generic classes. I don't know i'm wrong or right.This is the codepublic bool Compare<T1,T2>(T1 val1,T2 val2) { if (val1.Equals(val2)) return true; else return false; }
Lalit Raghav11y ago
Nice Article
Murugesh P11y ago
Thanks for the Simple and clear Example
Arun T12y ago
Nice article
Naveed Zaman12y ago
useful
Devesh Omar12y ago
Thanks Sir
Nimit Joshi12y ago
Very Good Explanation..
zeshan ajmal12y ago
nice article
Devesh Omar12y ago
Thanks Lakshmanan :)
Lakshmanan Sethu Sankaranarayan12y ago
Good one

Introduction

I would like to share the basics of generics. Here first we will learn the problem statement and then resolve the problem using Generics.

Problem statement

First create a class as in the following code.

class CompareClass {
public bool Compare(string x, string y) {
if (x.Equals(y)) return true;
else return false;
}
public bool Compare(int x, int y) {
if (x.Equals(y)) return true;
else return false;
}
}

Understanding the code

We created the CompareClass.

Here we created two compare methods, one for the string data type and the second for an int data type.

So the class contains overloaded compare functions.

Problem

So if we need to compare other datatypes like decimal, double and objects, then the code above would not work and we need to create another method to compare the proposed data type. We can solve this problem with generics.

Solution

Create a class as in the following code,

class CompareGenericClass < T > {
public bool Compare(T x, T y) {
if (x.Equals(y)) return true;
else return false;
}
}

Understanding the code

We created the class CompareGenericClass with the input parameter T so the class is CompareGenericClass<T>
Here T would be the datatype.
If we want to compare strings then the following style would be used to create an object of the class,
1. CompareGenericClass<string> Ocompare = new CompareGenericClass<string>();
2. bool stringResult=Ocompare.Compare("DEVESH", "DEVESH");
Since we passed T as a string the Compare method will accept only a string type of parameter.
We did the same for Interger as well.
1. CompareGenericClass<int> oIntcompare = new CompareGenericClass<int>();
2. bool integerresult=oIntcompare.Compare(5, 6);
Here with this class we do not need to overload the Compare method because this compare method accepts only a parameter that has been passed during creation of class objects.
Using this class we can avoid such problems that have been discussed above.

Output of code

Complete code

class CompareClass {
public bool Compare(string x, string y) {
if (x.Equals(y)) return true;
else return false;
}
public bool Compare(int x, int y) {
if (x.Equals(y)) return true;
else return false;
}
}
class CompareGenericClass < T > {
public bool Compare(T x, T y) {
if (x.Equals(y)) return true;
else return false;
}
}
class Program {
static void Main(string[] args) {
CompareClass obj = new CompareClass();
bool intresult = obj.Compare(5, 7);
Console.WriteLine("int comapre result:" + intresult);
bool stringresult = obj.Compare("DEVESH", "DEVESH");
Console.WriteLine("string comapre result:" + stringresult);
CompareGenericClass < string > Ocompare = new CompareGenericClass < string > ();
bool stringResult = Ocompare.Compare("DEVESH", "DEVESH");
Console.WriteLine("Generic string comapre result:" + stringResult);
CompareGenericClass < int > oIntcompare = new CompareGenericClass < int > ();
bool integerresult = oIntcompare.Compare(5, 6);
Console.WriteLine("Generic int comapre result:" + integerresult);
}
}

Conclusion

We have learned how to use a Generic class and why we need to use it.