如何将一个动作转换成同一个签名的定义的代理? [英] How to convert an action to a defined delegate of the same signature?
问题描述
class Test
{
public delegate void FruitDelegate(Fruit f);
public void Notify<T>(Action<T> del) where T : Fruit
{
FruitDelegate f = del; // Cannot implicitly convert type 'Action<T>' to 'FruitDelegate
}
}
$ b $水果是一个空类。这两个代表都有相同的签名。
Fruit is an empty class. Both of these delegates have the same signature.
我似乎没有任何工作。如果我解释了我正在做的事情(提供一些上下文),可能会有所帮助。
I cannot seem to get any of this working. Maybe it would help if I explained what I am trying to do (provide some context).
我想创建一个具有通用静态方法的类,提供一个类型和一个方法回调(像上面的例子)。
I want to create a class that has a generic static method that provides a type and a method callback (like the above example).
我遇到的问题是委托包含一个参数,我不想把它转换成方法回调。例如,我想要这样:
The problem I am having is that the delegate contains a parameter and I don't want to have to cast it within the method callback. For example, I want this:
public void SomeMethod()
{
Test.Notify<Apple>(AppleHandler);
}
private void AppleHandler(Apple apple)
{
}
而不是这样:
public void SomeMethod()
{
Test.Notify<Apple>(AppleHandler);
}
private void AppleHandler(Fruit fruit)
{
Apple apple = (Apple)fruit;
}
这样的事情可能吗?一直在工作几个小时,没有多少运气= /
Is this kind of thing possible? Have been working on it for a few hours without much luck =/
推荐答案
这是你想要的?
static void Main(string[] args)
{
Program p = new Program();
p.SomeMethod();
}
public class Fruit
{ }
public class Apple : Fruit { }
public delegate void FruitDelegate<in T>(T f) where T : Fruit;
class Test
{
public static void Notify<T>(FruitDelegate<T> del)
where T : Fruit, new()
{
T t = new T();
del.DynamicInvoke(t);
}
}
private void AppleHandler(Apple apple)
{
Console.WriteLine(apple.GetType().FullName);
}
public void SomeMethod()
{
FruitDelegate<Apple> del = new FruitDelegate<Apple>(AppleHandler);
Test.Notify<Apple>(del);
}
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