在两个字符串字段上实现IComparable接口

Question

如何在两个字符串字段上实现IComparable接口？

使用下面的Person类示例.如果将Person对象添加到列表中.如何根据Surname first THEN Forename对列表进行排序？

Class Person
{
    public string Surname { get; set; }
    public string Forname { get; set; }
}

就像是？:

myPersonList.Sort(delegate(Person p1, Person p2)
{
    return p1.Surname.CompareTo(p2. Surname);
});

Answer 1

或者你可以像这样排序一个列表:

myPersonList.Sort(delegate(Person p1, Person p2)
{
    int result = p1.Surname.CompareTo(p2.Surname);
    if (result == 0)
        result = p1.Forname.CompareTo(p2.Forname);
    return result;
});

或者,您可以使用此方法Person实现IComparable<Person>:

public int CompareTo(Person other)
{
    int result = this.Surname.CompareTo(other.Surname);
    if (result == 0)
        result = this.Forname.CompareTo(other.Forname);
    return result;
}

编辑正如Mark评论的那样,您可能决定需要检查空值.如果是这样,您应该决定是否应该将空值分类到顶部或底部.像这样的东西:

if (p1==null && p2==null)
    return 0; // same
if (p1==null ^ p2==null)
    return p1==null ? 1 : -1; // reverse this to control ordering of nulls