C# Default Value at Method - compile error : compile-time constant

private static Vector2 DefaultMulFactors = new Vector2(0.5f, 0.5f);
private static Point DefaultShifts = new Point(0,0);

public static Vector2 Function(Vector2? mulFactors = MyClass.DefaultMulFactors , Point? shifts = MyClass.DefaultShifts  )
{ 
    ...
    return result;
}

Why does my code not accept my static values? How can I assign开发者_C百科 default parameters to my function parameters? Indeed Vector2? mulFactors = new Vector(0.2,0.3) or Vector2? mulFactors = Vector2.Zero does not work.

You can't, basically. The value must be supported by the compiler to allow that type of usage (it is essentially a constant). I would just use null here:

, Point? shifts = null)

then:

if(shifts == null) shifts = MyClass.DefaultShifts;

From MSDN:

Each optional parameter has a default value as part of its definition. If no argument is sent for that parameter, the default value is used. A default value must be one of the following types of expressions:

a constant expression;

an expression of the form new ValType(), where ValType is a value type, such as an enum or a struct;

an expression of the form default(ValType), where ValType is a value type.

No one of mentioned cases is yours, that's why it doesn't work for you! :)