在两个字符串字段上实现 IComparable 接口

发布于 2024-08-06 14:26:28 字数 371 浏览 2 评论 0原文

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。如何根据姓氏在前，然后是名字对列表进行排序？

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

类似的东西？ :

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

原文

How do I implement the IComparable Interface on two string fields?

Using the Person class example below. If Person objects are added to a list. How do I sort the list based on Surname first THEN Forename?

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

Something like? :

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

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梦中楼上月下 2024-08-13 14:26:28

或者您可以像这样对列表进行排序：

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;
});

或者您可以使用以下方法让 Person 实现 IComparable：

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，您可能决定您需要检查空值。如果是这样，您应该决定是否应将 null 排序到顶部或底部。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

Or you could sort a list like this:

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;
});

Alternatively you could have Person implement IComparable<Person> with this method:

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

EDIT As Mark commented, you might decide you need to check for nulls. If so, you should decide whether nulls should be sorted to the top or bottom. Something like this:

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

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驱逐舰岛风号 2024-08-13 14:26:28

试试这个？

int surnameComparison = p1.Surname.CompareTo(p2.Surname);

if (surnameComparison <> 0)
  return surnameComparison;
else
  return p1.Forename.CompareTo(p2.Forename);

Try this?

int surnameComparison = p1.Surname.CompareTo(p2.Surname);

if (surnameComparison <> 0)
  return surnameComparison;
else
  return p1.Forename.CompareTo(p2.Forename);

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