I have an abstract class BaseClass
and want to enforce that all class Derived: BaseClass
have to override a method foo
resulting in a very specific signature. The Problem is as following:
foo
on their own (pref. only if they are not abstract) [like abstract
]virtual
]foo
in derived classes should be static
(the classes themself are not!) [eddit: omitted]]foo
are of class Derived
/this.GetType()
(pref. without changing signature of BaseClass)It is already hard enough/ impossible(?) to combine two of these (exept 4.), but maybe there are some clever workarounds and I take what I can get. At last here is some pseudo code to better reflect my intention:
public abstract class BaseClass
{
bool baseBool;
public abstract virtual static bool foo(BaseClass b1, BaseClass b2)
{
//sample code
return b1.baseBool ^ b2.baseBool;
}
}
public class Derived: BaseClass
{
bool derivedBool;
public static override bool foo(Derived d1, Derived d2)
{
//sample code
return base.foo(d1, d2) && d1.derivedBool ^ d2.derivedBool;
}
}
public abstract class BaseClass
{
bool baseBool;
public abstract bool foo(BaseClass b1, BaseClass b2);
}
public abstract class BaseClassWrappedCRTP<T>: BaseClass where T: BaseClassWrappedCRTP<T>
{
public override bool foo(BaseClass b1, BaseClass b2)
{
//sample code
return b1.baseBool ^ b2.baseBool && fooWrappedCRTP((T)b1, (T)b2);
}
protected abstract bool fooWrappedCRTP(T d1, T d2);
}
public class Derived: BaseClassWrappedCRTP<Derived>
{
bool derivedBool;
protected override bool fooWrappedCRTP(Derived d1, Derived d2)
{
//sample code
return d1.derivedBool ^ d2.derivedBool;
}
}
Note that if Derived were abstract class Derived: BaseClassWrappedCRTP<Derived>
, we would need abstract class DerivedWrappedCRTP<T>: Derived where T: DerivedWrappedCRTP<T>
to continue inheritance of foo
in this way (Given an actual need to access non-generic Derived
).
As mentioned in the comments inheritance and staticness don't fit.
From what you told I think this code might match your use case...
//declare the mixed lists with List<IBase> to get rid of the type params
interface IBase {
bool foo(BaseClass b1, BaseClass b2);
}
public abstract class BaseClass<T> : IBase where T : BaseClass
{
bool baseBool;
//If you call Foo from a "mixed list" use non generic, base class parameters, else you get casting troubles enumerating and calling 'foo'
public bool foo(BaseClass b1, BaseClass b2)
{
//sample code
return b1.baseBool ^ b2.baseBool && fooOverride((T)b1, (T)b2);
}
protected abstract bool fooOverride(T b1, T b2);
}
public class Derived : BaseClass<Derived>
{
bool derivedBool;
protected override bool fooOverride(Derived d1, Derived d2)
{
//sample code
return d1.derivedBool ^ d2.derivedBool;
}
}