Question

我有以下类层次结构

public class EntityBase<T> where T : EntityBase<T>
{
    //nothing interesting here
}

public class Benefit : EntityBase<Benefit>
{
    //again, nothing interesting here
}

public class SeasonTicketLoan : Benefit
{
    //nothing interesting here
}

现在我有了以下界面

public interface IQuery<T> where T : EntityBase<T>
{
}

当我尝试构建以下类时，我得到编译错误

public class EmployeesQuery : IQuery<SeasonTicketLoan>
{
}

我收到一条错误，指出SeasonTicketLoan类不满足约束条件。

Answer 1

Benefit类也应该具有泛型类型 - 因此所有父类都将＆＃34; ultimate＆＃34; / sealed类型作为其泛型类型。只有＆＃34;终极＆＃34; /密封类型没有通用参数。
结果是在所有父类中，一直到根父类，泛型参数包含＆＃34;终极＆＃34; /密封类的类型，并且不会出现错误。

public class EntityBase<T> where T : EntityBase<T>
{
    //nothing interesting here
}

public class Benefit<T> : EntityBase<T> where T : Benefit<T>
{
    //again, nothing interesting here
}

public sealed class SeasonTicketLoan : Benefit<SeasonTicketLoan>
{
    //nothing interesting here
}

C＃ - 如何为多级继承层次结构指定泛型类型约束？

1 个答案: