C# - 我怎样才能“重载"?代表? [英] C# - How can I "overload" a delegate?

问题描述

首先，我阅读了一些论坛和 MSDN 中的帮助，都说不能重载代理.

First, I was reading some forums and the help in MSDN and all says that a delegate can't be overloaded.

现在，我想要这样的东西:

Now, I want to have something like this:

public delegate void OneDelegate();
public delegate void OneDelegate(params object[] a);

public void DoNothing(params object[] a) {}
public void DoSomething() { /* do something */ }

private OneDelegate someFunction;

someFunction = new OneDelegate(DoSomething);
someFunction = new OneDelegate(DoNothing);

所以，如您所知，您不能这样做，因为 OneDelegate 仅引用第一个而不是第二个.但是，有没有办法做到这一点?或类似的东西?

So, like you know, you CAN'T do this, because OneDelegate only refers to the first one and not the second one. But, is there a way for doing this? or something like that?

PS1:我希望拥有任意数量的 OneDelegate 声明，而不仅仅是一两个.

PS1: I want to have any number of OneDelegate declarations, not just one or two.

推荐答案

想象一下这是可能的.假设我可以有一个重载的委托:

Imagine for a moment this was possible. Suppose I could have an overloaded delegate:

public delegate void OneDelegate(int i);
public delegate void OneDelegate(string s);

现在假设我声明了一个这种类型的变量，然后给它分配了一个函数，例如:

Now imagine I declare a variable of this type and then assign a function to it, for example:

OneDelegate myDelegate = StringMethod;

StringMethod 是这样声明的:

public void StringMethod(string s) { Console.WriteLine(s); }

现在您将 myDelegate 传递给其他代码，该代码执行以下操作:

Now you pass myDelegate to some other code, and that code does this:

myDelegate(47);

您希望在这种情况下会发生什么?运行时如何调用带有整数参数的StringMethod()?

What do you expect to happen in this case? How can the runtime call StringMethod() with an integer argument?

如果你真的想要一个可以接受任何参数集的委托，那么唯一的选择就是有一个带有 params object[] 数组的委托:

If you really want a delegate that can take any set of parameters at all, then the only option is to have one with a params object[] array:

public delegate void OneDelegate(params object[] parameters);

但是你必须为它分配一个可以实际处理任何对象数组的函数，例如:

But then you will have to assign to it a function that can actually handle any object array, for example:

public void MyMethod(params object[] parameters)
{
    if (parameters == null || parameters.Length == 0)
        throw new ArgumentException("No parameters specified.");
    if (parameters.Length > 1)
        throw new ArgumentException("Too many parameters specified.");

    if (parameters[0] is int)
        IntMethod((int) parameters[0]);
    else if (parameters[0] is string)
        StringMethod((string) parameters[0]);
    else
        throw new ArgumentException("Unsupported parameter type.");
}

如您所见，这很快就会变得一团糟.因此，我向您提出，如果您需要这样的代表，您可能在建筑设计的某个地方犯了错误.在继续实施之前识别此缺陷并修复设计，否则代码的可维护性将受到影响.

As you can see, this gets messy real quick. Therefore, I submit to you that if you need such a delegate, you have probably made a mistake somewhere in your architectural design. Identify this flaw and fix the design before you proceed with the implementation, as otherwise the maintainability of your code will suffer.

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