Lambda for getter and setter of property

C# 7 brings support for setters, amongst other members:

More expression bodied members

Expression bodied methods, properties etc. are a big hit in C# 6.0, but we didn’t allow them in all kinds of members. C# 7.0 adds accessors, constructors and finalizers to the list of things that can have expression bodies:

class Person
{
    private static ConcurrentDictionary<int, string> names = new ConcurrentDictionary<int, string>();
    private int id = GetId();

    public Person(string name) => names.TryAdd(id, name); // constructors
    ~Person() => names.TryRemove(id, out _);              // finalizers
    public string Name
    {
        get => names[id];                                 // getters
        set => names[id] = value;                         // setters
    }
}

First of all, that is not lambda, although syntax is similar.

It is called "expression-bodied members". They are similar to lambdas, but still fundamentally different. Obviously they can't capture local variables like lambdas do. Also, unlike lambdas, they are accessible via their name:) You will probably understand this better if you try to pass an expression-bodied property as a delegate.

There is no such syntax for setters in C# 6.0, but C# 7.0 introduces it.

private int _x;
public int X
{
    get => _x;
    set => _x = value;
}