无法将受保护的枚举作为静态方法的参数传递

Question

I've been updating the company's software and stumbled upon this problem. There's this enum that's protected and I want to pass a value from that enum as a parameter for a static method, but I can't cause I have no access to it even though both the method and the enum are in the same class.

Example:

Class SomeClass
{    
    protected enum Car
    {
        Id
    };

    public static void AMethod(Car enumValue)
    {
        MessageBox.Show("This is an enum:" + enumValue.ToString());
    }  
}

I can't use this Car enumValue as parameter for AMethod cause I have no access to it. Why can't I do this? I mean they're in the same class. Am I missing something?

Answer 1

The issue is not that your SomeClass can't see the enum. The problem is your enum has a protected access modifier, and you're trying to use it in a public method (ie accessible outside your class). You can't expose a protected type through a public member because methods in other classes can't see the enum when they're trying to call AMMethod() .

Depending on how you intend to use this class, you need to change either one or the other so the access modifiers match:

public enum Car
{
    Id
};

public static void AMethod(Car enumValue)
{
    MessageBox.Show("This is an enum:" + enumValue.ToString());
}  

or:

protected enum Car
{
    Id
};

protected static void AMethod(Car enumValue)
{
    MessageBox.Show("This is an enum:" + enumValue.ToString());
}  

The latter one will just prevent the compiler error, but it may be the case that you want AMethod to be public, so you should choose the former.