OOP Class Design

Question

I have this code,

public abstract class BaseClass
{
    public object CommonMethod<T>()
    {
        //Common code

        CustomMethod(); //Call child method

        return (T)CustomObject;
    }

    internal abstract void CustomMethod();
}


public class ChildClass : BaseClass
{
    public MyDTO CommonMethod()
    {
        return (MyDTO)base.CommonMethod<MyDTO>(); //Call Base class common code
    }

    internal override void CustomMethod()
    {
        //Custom Code, specific to child class
    }
}

I have some common code which I have placed in the base class (BaseClass.CommonMethod), But finally same method should run child class specific code (ChildClass.CustomMethod).

Is this implementation correct or is there any other preferred/better implementation to achieve this?

EDIT

Final code (Updated according to the answers) :

public abstract class BaseClass<T> where T : IDTO
{
    public T CommonMethod()
    {
        //Common code

        CustomMethod(); //Call child method

        return (T)CustomObject;
    }

    internal abstract void CustomMethod();
}


public class ChildClass : BaseClass<MyDTO>
{
    internal override void CustomMethod()
    {
        //Custom Code, specific to child class
    }
}

Answer 1

With small corrections your code looks good. You don't need to override CommonMethod, though, if you put return value as T:

public abstract class BaseClass<T>
{
    public T CommonMethod()
    {
        //Common code

        T result = CustomMethod(); //Call child method

        return result;
    }

    internal abstract T CustomMethod();
}

public class ChildClass : BaseClass<MyDTO>
{
    internal override MyDTO CustomMethod()
    {
        //Custom Code, specific to child class
    }
}

In my example I assumed that you return CustomObject from CustomMethod, otherwise I'm not quite sure where are you getting this object from.

Answer 2

I don't think you need the cast (MyDTO)base.CommonMethod<MyDTO>(); as your base method is already casting the result.

You will need to make sure that CustomObject can be cast to T, that bit looks fishy to me.

CustomerObject must inherit from MyDTO, therefore T must implement MyDTO (I think)