Question about "readonly"

Tommy Sin

Hello,

I am just wondering how I could add elements to the Dictionary below even if it is declared as readonly.
Are we not supposed to be able to modify the dictionary if it is declared as readonly?
Thanks.

class program
{
        private static readonly Dictionary _dictionary = new Dictionary();
        static void Main(string[] args)
        {
                _dictionary.Add("a",1);
                _dictionary.Add("b",2);
                _dictionary.Add("c",3);
        }
}

5 Replies

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Vulpes15y ago
Accepted answer
You can still add elements to the Dictionary if it's declared as read only.

What you can't do is to assign a different Dictionary object to it which can only be done from the constructor or 'in situ'.
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Vulpes15y ago
I'm surprised you haven't heard of it, Sam, as I don't think it's uncommon.

It's just a Latin phrase which means "in the original position".
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Sam Hobbs15y ago
Tommy, don't feel bad about not knowing what "situ" means. I have been programming for many years and speaking English my whole life and I have never heard it.
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Vulpes15y ago
I mean where it's declared.

So, in your code, you've assigned a new Dictionary object to the readonly field _dictionary when you've declared it or 'in situ'.

As it's a private static field, you can add elements to it (or remove elements from it) from any instance or static method in the program class but you can't change the actual Dictionary object itself.
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Tommy Sin15y ago
Hello,

Thanks for your explanation.

By the way, what do you mean by 'in situ'?

Thanks
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