c# – 我应该在类中使用Field或Property来设置值

public sealed class NewObject
{
    private string _stuff = string.Empty;

    public string Stuff
    {
        get { return GetAllStuff(); }
    }

    private string GetAllStuff()
    {
        //Heavy string manipulation of _stuff
    }

    public NewObject(string stuffToStartWith)
    {
        _stuff = stuffToStartWith;
    }

    public static NewObject operator +(NewObject obj1,NewObject obj2)
    {
        if (obj1 == null)
            throw new ArgumentNullException();

        if (obj2 == null)
            throw new ArgumentNullException();

        NewObject result = new NewObject(string.Empty);
        result._stuff = String.Concat(obj1._stuff,obj2._stuff);

        return result;
    }
}

争论在于运算符覆盖.我的同事认为,除了构造函数之外,设置私有字段的值不是最好的编程习惯.我的同事提出的解决方案是将Stuff属性的名称重构为AllStuff,并添加一个属性Stuff,它具有get AND set访问器并在运算符覆盖中使用新的Stuff属性.看起来像这样：

public static NewObject operator +(NewObject obj1,NewObject obj2)
    {
        if (obj1 == null)
            throw new ArgumentNullException();

        if (obj2 == null)
            throw new ArgumentNullException();

        NewObject result = new NewObject(string.Empty);
        result.Stuff = String.Concat(obj1.Stuff,obj2.Stuff);

        return result;
    }

我不同意.我觉得第一种方式更好,因为它使属性在类外保持只读.我的问题是,哪种方式是面向对象设计的最佳实践？