C# : How does this work : Unit myUnit = 5;

Question

I just noticed that you can do this in C#:

Unit myUnit = 5;

instead of having to do this:

Unit myUnit = new Unit(5);

Does anyone know how I can achieve this with my own structs? I had a look at the Unit struct with reflector and noticed the TypeConverter attribute was being used, but after I created a custom TypeConverter for my struct I still couldn't get the compiler to allow this convenient syntax.

Answer 1

You need to provide a cast operator for the class that takes an Int32.

Answer 2

You need to provide an implicit conversion operator from int to Unit, like so:

    public struct Unit
    {   // the conversion operator...
        public static implicit operator Unit(int value)
        {
            return new Unit(value);
        }
        // the boring stuff...
        private readonly int value;
        public int Value { get { return value; } }
        public Unit(int value) { this.value = value; }
    }