我可以有一个动作<>或FUNC。<>带出参数？ [英] Can I have an Action<> or Func<> with an out param?

问题描述

我用退出参数的方法，我想指出一个动作或<$ 。C $ C>函数功能（或其他类型的委托），它

I have a method with an out parameter, and I'd like to point an Action or Func (or other kind of delegate) at it.

这工作得很好：

static void Func(int a, int b) { }
Action<int,int> action = Func;

尽管如此，这并不

However this doesn't

static void OutFunc(out int a, out int b) { a = b = 0; }
Action<out int, out int> action = OutFunc; // loads of compile errors

这可能是重复的，但搜索出参数'ISN尤其不丰硕的成果。

This is probably a duplicate, but searching for 'out parameter' isn't particularly fruitful.

推荐答案

Action和Func键特别不拿出或ref参数。然而，他们只是委托。

Action and Func specifically do not take out or ref parameters. However, they are just delegates.

您可以使确实需要out参数自定义的委托类型，并使用它，但。

You can make a custom delegate type that does take an out parameter, and use it, though.

例如，下面的工作：

class Program
{
    static void OutFunc(out int a, out int b) { a = b = 0; }

    public delegate void OutAction<T1,T2>(out T1 a, out T2 b);

    static void Main(string[] args)
    {
        OutAction<int, int> action = OutFunc;
        int a = 3, b = 5;
        Console.WriteLine("{0}/{1}",a,b);
        action(out a, out b);
        Console.WriteLine("{0}/{1}", a, b);
        Console.ReadKey();
    }
}

这打印出来：

3/5
0/0

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