C# derived classes and properties

Question

I have the following classes. For each of the control classes, I'd like to expose the data member via a property.

public class BasicData {}
public class AdvancedData : BasicData { }

public class BasicControl
{
    private BasicData data;

    public BasicData DataHide;

    public virtual BasicData DataOverride;
}

public class AdvancedControl: BasicControl
{
    private AdvancedData data;

    public new AdvancedData DataHide; //Hide

    public override BasicData DataOverride; //Override
}

If I make the property virtual, then my AdvancedControl class has to expose the data as BasicData and not AdvancedData (which I'd prefer).

I can instead hide the base class's property but I've read that hiding should be avoided where possible.

I want to have just one data property exposed for each Control class and I want this property to have the same name in each class i.e. Data. For BasicControl this should be BasicData. For AdvancedControl this should be AdvancedData.

What's the best way of designing my classes to achieve this?

Can't you use generics? `BasicControl where TData : BasicData`? — Toxantron, Jun 17 '16 at 13:59
I would use generics have just have `Control where T: BasicData` and have `Data` as `private T data;`. `AdvancedControl` would then be `class AdvancedControl: Control` — Bradley Uffner, Jun 17 '16 at 14:01
http://stackoverflow.com/questions/5709034/does-c-sharp-support-return-type-covariance — Matteo Umili, Jun 17 '16 at 14:03

score 1 · Accepted Answer · answered Jun 17 '16 at 14:03

You could use a generic approach:

public class BasicData {}
public class AdvancedData : BasicData { }

public class BasiccControl<T> where T : BasicData
{
    private T data;
    public T Data;
}

public class AdvancedControl : BasicControl<AdvancedData>
{
}

So you don't need to override or hide the members in each derivate and still have type safety (as long as you provide the correct generic arguments for T).

C# derived classes and properties

1 Answers1