如何定義繼承通用抽象類的通用抽象類？

Question

我有一個繼承一個抽象類的類，該抽象類又繼承了另一個抽象類。 我可以將最高級的類定義為泛型，但是在最終ListResults類中表達所需的實際類型之前，我不知道如何將中級類定義為泛型。

internal abstract class LowerCommand<T> {
    public abstract void Execute();
    public abstract List<T> ExecuteList();
}

// currently gives error for `T`
internal abstract class HigherCommand : Lowercommand<T> {
    // ... defines other stuff, nothing to do with
    //     already instantiated methods or T ...
}

class ListResults : HigherCommand<Results>
{
    public override void Execute() {...}
    public override List<Results> ExecuteList() {...}
}

謝謝你的幫助。

Answer 1

您仍然需要在HigherCommand的定義上定義通用類型參數T ，以便可以依次正確定義LowerComand 。

internal abstract class LowerCommand<T> {
    public abstract void Execute();
    public abstract List<T> ExecuteList();
}

// Note that HigherCommand require a declaration of `T`
internal abstract class HigherCommand<T> : Lowercommand<T> {
    // ... defines other stuff, nothing to do with
    //     already instantiated methods or T ...
}

class ListResults : HigherCommand<Results>
{
    public override void Execute() {...}
    public override List<Results> ExecuteList() {...}
}