c# - 如何创建具有反射类型的委托(delegate)闭包

Question

如何创建一个使用反射类型参数的闭包？以 .net 3.5 为目标

如果没有反射(reflection)我会

void Main()
{
    int i = 0;
    Action<Foo> doSomething = (foo) => i += foo.GetNumber();
    var myFoo = new Foo();
    myFoo.UseFoo(doSomething);
    Console.WriteLine(i);
}

class Foo
{
    public int GetNumber() { return 4; }
    public void UseFoo(Action<Foo> doSomething)
    {
        doSomething(this);
    }
}

当 Foo 是通过另一个程序集反射获得的类型时，我将如何设置 doSomething？

void Main()
{
    Type fooType = GetType("Foo");
    int i = 0;
    object doSomething = // ???;

    var myFoo = Activator.CreateInstance(fooType);
    fooType.GetMethod("UseFoo").Invoke(myFoo, new object[] { doSomething });
    Console.WriteLine(i);
}

Answer 1

我使用了 DocXcz 和 Nikola Anusev 的答案来解决这个问题

static void Main()
{
    var fooType = typeof(Foo); // get type via any method
    int i = 0;

    Action<object> doSomething = (foo) => i += (int)foo.GetType().GetMethod("GetNumber").Invoke(foo, null);
    var typedDoSomething = (typeof(Program)).GetMethod("DelegateHelper").MakeGenericMethod(fooType).Invoke(null, new object[] { doSomething });

    var myFoo = Activator.CreateInstance(fooType);
    fooType.GetMethod("UseFoo").Invoke(myFoo, new object[] { typedDoSomething });
    Console.WriteLine(i);
}

public static Action<T> DelegateHelper<T>(Action<object> generic)
{
    return x => generic(x);
}

基本上我需要使用一个通用的辅助方法来转换 Action<object>到Action<T>在运行时确定