Question

我有一个接口和一个派生类型

public interface ITransformationRule<in TSource, in TResult, in TContext> {...}
public class MyRule : ITransformationRule<object, object, object> {...}

然后我有一个规则引擎，它有以下方法

public class RuleEngine<TContext>
{
    public void Register<TRule, TSource, TResult>() // I would like to keep it just Register<TRule> but compiler would not let me
        where TRule : ITransformationRule<TSource, TResult, TContext> {...}
}

现在我想在某处注册该规则：

var engine = new RuleEngine<object>();
engine.Register<MyRule>(); // this fails to compile
engine.Register<MyRule, object, object>(); // this is OK

问题是如何只使用一个类型参数（MyRule）调用Register方法，而不必指定TSource和TResult？我知道我可以放弃约束，但我打算保留它。

Answer 1

试试这个：

public interface ITransformationRule<in TSource, in TResult, in TContext> {}
public class MyRule : ITransformationRule<object, object, object> {}

public class RuleEngine<TContext, TSource, TResult>
{
    public void Register<TRule>() // I would like to keep it just Register<TRule> but compiler would not let me
        where TRule : ITransformationRule<TSource, TResult, TContext>
    {

    }

}

var engine = new RuleEngine<object, object, object>();
engine.Register<MyRule>();

编辑：使用JakubDąbek方法

public interface ITransformationRule<in TSource, in TResult, in TContext> { }
public class MyRule : ITransformationRule<object, object, object> { }

public class RuleEngine<TContext>
{
    public void Register<TRule>() // I would like to keep it just Register<TRule> but compiler would not let me
        where TRule : ITransformationRule<object, object, TContext>
    {

    }

}

var engine = new RuleEngine<object>();
engine.Register<MyRule>();

用作类型约束时的接口逆转

1 个答案: