It is 2nd Part of Inheritance in C# for Multi-Level
Generally, c# supports only single inheritance that means a class can only inherit from one base class. However, in c# the inheritance is transitive, and it allows you to define a hierarchical inheritance for a set of types, and it is called a multi-level inheritance.
For example, if class C is derived from class B, and class B is derived from class A, then class C inherits the members declared in both class B and class A.
public class A
{
// Implementation
}
public class B: A
{
// Implementation
}
public class C: B
{
// Implementation
}
If you observe the above code snippet, class C is derived from class B, and class B is derived from class A, then class C inherits the members declared in both class B and class A. This is how we can implement multi-level inheritance in our applications.
Multi-Level Inheritance Example
Following is the example of implementing multi-level inheritance in the c# programming language.
using System;
namespace ArjunInheritance
{
public class A
{
public string Name;
public void GetName()
{
Console.WriteLine("Name: {0}", Name);
}
}
public class B: A
{
public string Location;
public void GetLocation()
{
Console.WriteLine("Location: {0}", Location);
}
}
public class C: B
{
public int Age;
public void GetAge()
{
Console.WriteLine("Age: {0}", Age);
}
}
class Program
{
static void Main(string[] args)
{
C c = new C();
c.Name = "Arjun Walmiki";
c.Location = "Thane";
c.Age = 35;
c.GetName();
c.GetLocation();
c.GetAge();
Console.WriteLine("\nPress Any Key to Exit..");
Console.ReadLine();
}
}
}
If you observe the above example, we implemented three classes (A, B, C), and class C is derived from class B, and class B is derived from class A.
By implementing a multi-level inheritance, class C can inherit the members declared in class B and class A.
When you execute the above c# program, you will get the result as shown below.
Name : Arjun Walmiki
Location : Thane
Age : 35
Press Any Key to Exit..
Multiple Inheritance
As discussed, c# supports only single inheritance that means a class can only inherit from one base class. If we try to inherit a class from multiple base classes, then we will get compile-time errors.
For example, if class C is trying to inherit from Class A and B simultaneously, we will get a compile-time error because multiple inheritance is not allowed in c#.
public class A{
// Implementation
}
public class B
{
// Implementation
}
public class C: A, B
{
// Implementation
}
If you observe the above code snippet, class C is trying to inherit properties from both classes A and B simultaneously, which will lead to compile-time errors like “Class C cannot have multiple classes: A and B”.
As discussed, multi-level inheritance is supported in c#, but multiple inheritance is not supported. If you want to implement multiple inheritance in c#, we can achieve this by using interfaces. In the next chapters, we will learn how to use interfaces to achieve multiple inheritance in a detailed manner.
