Immutable object pattern in C# - what do you think? [closed]

Answer 1

You can use optional named arguments together with nullables to make an immutable setter with very little boilerplate. If you really do want to set a property to null then you may have some more troubles.

class Foo{ 
    ...
    public Foo 
        Set
        ( double? majorBar=null
        , double? minorBar=null
        , int?        cats=null
        , double?     dogs=null)
    {
        return new Foo
            ( majorBar ?? MajorBar
            , minorBar ?? MinorBar
            , cats     ?? Cats
            , dogs     ?? Dogs);
    }

    public Foo
        ( double R
        , double r
        , int l
        , double e
        ) 
    {
        ....
    }
}

You would use it like so

var f = new Foo(10,20,30,40);
var g = f.Set(cat:99);