Can anyone explain me what they mean by 'favor object composition over

yes, obviously composition is preferred over the inheritance.

public class BaseClass
{
public string property { get; set; }
public void BaseMethod()
{
// Do something....
}
}
public class DerivedClass : BaseClass
{
public string DerivedclassProperty { get; set; }
public void DerivedMethod()
{
// Do something....
base.BaseMethod();
}
}

we don't use the above thing mostly we prefer to use composition as shown below

public class FirstClass
{
public string property { get; set; }
public void FirstMethod()
{
// Do something....
}
}
public class SecondClass
{
private FirstClass firstClass = new FirstClass();
public string ClassProperty { get; set; }
public void MyMethod()
{
// Do something....
firstClass.FirstMethod();
}
}

so, instead of extending the FirstClass, we generally compose it inside the related class, this is the most common scenario where there is a "Has-a" relation between 2 entities. Like Department has employees. so List will be used as property inside the Department, there is no need of inheritance at all.

3 Replies

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Sachin Singh5y ago
Accepted answer
yes, obviously composition is preferred over the inheritance.
public class BaseClass
{
    public string property { get; set; }

    public void BaseMethod()
    {
        // Do something....
    }
}

public class DerivedClass : BaseClass
{
    public string DerivedclassProperty { get; set; }

    public void DerivedMethod()
    {
        // Do something....
        base.BaseMethod();
    }
}
we don't use the above thing mostly we prefer to use composition as shown below
public class FirstClass
{
    public string property { get; set; }

    public void FirstMethod()
    {
        // Do something....
    }
}

public class SecondClass
{
    private FirstClass firstClass = new FirstClass();
    public string ClassProperty { get; set; }

    public void MyMethod()
    {
        // Do something....
        firstClass.FirstMethod();
    }
}
so, instead of extending the FirstClass, we generally compose it inside the related class, this is the most common scenario where there is a "Has-a" relation between 2 entities. Like Department has employees. so List will be used as property inside the Department, there is no need of inheritance at all.
Sanjay Kumar5y ago
Thank you
Rajanikant Hawaldar5y ago
Check Composition_over_inheritance