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How to include an "empty" constant in a class

I have a class and I would like to include an "Empty" constant member similar to Point.Empty in System.Drawing. Is it possible?

Here's a simplified version of what is giving the error:

public class TrivialClass
{
    public const TrivialClass Empty = new TrivialClass(0);
    public int MyValue;
    public TrivialClass(int InitialValue)
    {
        MyValue = InitialValue;
    }
}

The error indicated: TrivialClass.Empty is of type TrivialClass. A const field of a reference type other than a string can only be initialized to zero.

If it matters, I would like to use it like this:

void SomeFunction()
{
    TrivialClass myTrivial = TrivialClass.Empty;
    // Do stuff ...
}
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2 answers


You can use static readonly

for these types. Constants can only be initialized with literal values ​​(e.g. numbers, strings).

public class TrivialClass
{
    public static readonly TrivialClass Empty = new TrivialClass(0);
    public int MyValue;
    public TrivialClass(int InitialValue)
    {
        MyValue = InitialValue;
    }
}


After looking for a definition. Point.Empty

also static readonly

. Link here .

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Just shoot fast, but I would assume Point.Empty is a static member, not a constant:



public class TrivialClass
{
    public static readonly TrivialClass Empty = new TrivialClass(0);
    ...
}
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