具有泛型类型检查的泛型方法调用

Question

我正在尝试概括一些构建器重复方法调用。我有一些实体，如果它们已经实现了一些接口，我会尝试实现调用标准方法。这是我试图在代码中实现的目标：

void MainMethod(){
  ...
  HandleStandards<MyClass>(builder);
  ...
}

void HandleStandards<T>(..builder..) where T: class, IEntity
{
  // of course my problem is with here. because T is not suitable to pass to other methods

  if(T is IIdentifiable){
    HandleIdentifiable<T>(builder);
  }
  if(T is ITrackable){
    HandleTrackable<T>(builder);
  }
}

void HandleIdentifiable<T>(..builder..) where T: class, IEntity, IIdentifiable
{
  ...
}

void HandleTrackable<T>(..builder..) where T: class, IEntity, ITrackable
{
  ...
}

有没有办法对泛型类型进行类型检查并将其传递给另一个泛型方法？

Answer 1

你可以做到这一点，使用一些反射魔法，或者，如果你的 HandleStandards 有一个类型为 T 的参数，你可以更容易地做到这一点。所以首先，让我们看看如果 builder 的类型是 T:

怎么办

void HandleStandards<T>(T builder) where T: class, IEntity
{
    if (builder is IIdentifiable identifiable)
    {
        HandleIdentifiable(identifiable)
    }

    // You'd go on like this
}

如果你没有T类型的参数，我们将不得不使用一些反射魔法来做到这一点，但它不是很多，这里是：

void Handle Standards<T>() where T : class, IEntity
{
    if (typeof(T).IsAssignableTo(typeof(IIdentifiable)))
    {
        // You'll probably have to use some BindingFlags
        // Here I'm assuming that 'HandleIdentifiable' is private and static
        // https://docs.microsoft.com/en-us/dotnet/api/system.reflection.bindingflags?view=net-6.0
        var method = typeof(TypeContainingTheseMethods).GetMethod(
            nameof(HandleIdentifiable),
            BindingFlags.NonPublic | BindingFlags.Static
        );

        // If the method is *not* static, you'll need to pass the instance
        // on which to call the method on as the first parameter instead of null
        // Plus any additional parameters you may have inside the object array
        // in the same order as the method declares them
        method.MakeGenericMethod(typeof(IIdentifiable))
           .Invoke(null, new object[] { builder });
    }
}

具有泛型类型检查的泛型方法调用

Generic method calls with generic type checks

c#

abstraction