c# - 具有非空保护子句的自动实现的属性？

Question

我同意 Mark Seeman 的观点，即 Automatic Properties are somewhat evil因为他们打破了封装。然而，我确实喜欢它们带来的简洁语法、可读性和便利性。

我引用:

public string Name { get; set; }

The problem with the code snippet isn’t that it contains too much ceremony. The problem is that it breaks encapsulation. In fact

“[…] getters and setters do not achieve encapsulation or information hiding: they are a language-legitimized way to violate them.”

James O. Coplien & Gertrud Bjørnvig. Lean Architecture. Wiley. 2010. p. 134.

大多数时候，添加一个非 null 保护子句对于属性 setter 来说已经足够了，我想知道是否有比以下方法更好的方法。我所说的更好，是指以更简洁/更少重复的方式。

使用代码契约:

private string _username;
public virtual string Username
{
    get { return _username; }
    set 
    {  
        Contract.Requires(value != null);
        _username = value; 
    }
}

使用 Vanilla .NET:

private string _username;
public virtual string Username
{
    get { return _username; }
    set 
    {
        if (value == null) throw new ArgumentNullException("Username");
        _username = value; 
    }
}

Answer 1

我只引用 Code Contracts手册，§ 2.3.1:

public int MyProperty { get; private set ; }

[ContractInvariantMethod]
private void ObjectInvariant () 
{
      Contract. Invariant ( this.MyProperty >= 0 );
      ...
}