Is range variable possible in C# (.NET)

Question

I'm looking for some class or data type to allow me define a range for it.
This is the pseudo code which I'm looking for :

[Range(0, 75)] int ChildAge;

This range rule should be applied to any int which this Age is assigned like following

var MotherAge = ChildAge;
MotherAge = 100; 

MotherAge should be set to 75 and this is what I'm looking for.

Answer 1

Another option would be to define your own data type to represent age values. This type could enforce the constraints.

struct Age
{
    const int MinAge = 0;
    const int MaxAge = 75;

    readonly byte value;

    public int Value { get { return value; } }

    private Age(int value) {
        this.value = (byte) Math.Max(MinAge, Math.Min(MaxAge, value));
    }

    public static implicit operator Age(int value) {
        // Throw here if value is out of range, maybe?
        return new Age(value);
    }

    public static implicit operator int(Age age) {
        return age.value;
    }
}

    //usage:
    Age childAge = 12; // 12
    Age motherAge = 100; // 75

Edit: I would point out that it is generally considered bad practice to have "lossy" conversions exposed as implicit casts. I should have made the operator int(Age) conversion explicit instead. This would require writing an explicit cast Age age = (Age) 100; which advertises to the consumer of the API that the cast isn't "identity preserving". This is similar to a cast from long to int or double to float, there is a loss of range/precision so the language requires you be explicit about it to demonstrate that you understand what you are doing.