Attribute to generate compilation error on method call?
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 runtim开发者_运维技巧e. 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()
{
}
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...
For completeness, here's more details about why I need to do that :
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);
}
}
(Note the way I create the T instance using Activator.CreateInstance
)
I can then use it with a class like that :
private class Foo
{
protected Foo()
{
}
public string Bar { get; private set; }
}
And call Singleton<Foo>.Instance
to access the instance.
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.
So, is there an attribute similar to ObsoleteAttribute
that would generate an error instead of a warning ?
Any suggestion would be appreciated
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)]
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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