属性生成的方法调用编译错误？ [英] Attribute to generate compilation error on method call?

问题描述

我想确保一个方法（实际上在我的情况下，构造函数）决不会从code显式调用。它应该只通过在运行时反射被调用。为了做到这一点，我想申请上会产生一个编译器错误的方法的属性，如果该方法被调用时，是这样的：

I would like to ensure that a method (actually a constructor in my case) is never called explicitly from code. It should only be called through reflection at runtime. To do that, I would like to apply an attribute on the method that would generate a compiler error if the method is called, something like :

[NotCallable("This method mustn't be called from code")]
public void MyMethod()
{
}

我知道我可以做的方法私有的，但在这种情况下，我不能够在部分信任上下文来调用它通过反射...

I know that I could make the method private, but in that case I wouldn't be able to call it through reflection in a partial trust context...

有关完整，这里就是为什么我需要做的更多详细信息：

For completeness, here's more details about why I need to do that :

我实现一个可重复使用辛格尔顿＆LT; T＆GT; 类的基础上的乔恩斯基特的文章。这里是我的code迄今：

I'm implementing a reusable Singleton<T> class, based on Jon Skeet's article. Here's my code so far :

public static class Singleton<T>
{
    public static T Instance
    {
        get
        {
            return LazyInitializer._instance;
        }
    }

    private class LazyInitializer
    {
        // Explicit static constructor to tell C# compiler
        // not to mark type as beforefieldinit
        static LazyInitializer()
        {
            Debug.WriteLine(string.Format("Initializing singleton instance of type '{0}'", typeof(T).FullName));
        }

        internal static readonly T _instance = (T)Activator.CreateInstance(typeof(T), true);
    }
}

（注意：我创建使用T实例的方式 Activator.CreateInstance ）

然后我可以用这样的类使用它：

I can then use it with a class like that :

private class Foo
{
    protected Foo()
    {
    }

    public string Bar { get; private set; }
}

和呼叫辛格尔顿＆LT;富方式＆gt; .Instance 来访问实例

在部分信任，它不会工作，因为富的构造是不公开的。但是，如果我把它公开，什么都不会prevent从code调用它明确。我知道我可以适用 ObsoleteAttribute 在富的构造函数，但只会生成一个警告，许多人不理会警告。

In partial trust, it won't work because the Foo constructor is not public. But if I make it public, nothing will prevent calling it explicitly from code... I know I could apply the ObsoleteAttribute on the Foo constructor, but it will only generate a warning, and many people just ignore warnings.

那么，有没有类似 ObsoleteAttribute 属性，将产生一个错误，而不是警告呢？

So, is there an attribute similar to ObsoleteAttribute that would generate an error instead of a warning ?

任何建议将AP preciated

Any suggestion would be appreciated

推荐答案

您可以使用 ObsoleteAttribute构造，需要一个布尔值，使用它可以表明调用的方法是一个编译错误：

You can use the ObsoleteAttribute constructor that takes a boolean with which you can indicate that calling the method is a compilation error:

[Obsolete("Don't use this", true)]

不过，如果我是你，我会重新考虑我的设计，因为这样做是不是一个精心设计的API的一个标志。

However, if I were you, I'd reconsider my design, as doing this isn't a sign of a well-designed API.

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