c# - 获取两个列表之间的差异

Question

我有两个列表(ListA 和ListB)，这些列表的类型都是相同的PersonInfo，Login字段是唯一键。

public class PersonInfo
{
    public string Login { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public int Age { get; set; }
    public bool Active { get; set; }
}

我想比较这两个列表:

1. 我想获取 ListA 中的项目列表，但在 ListB

   中不可用>

2. 对于两个列表中可用的项目，我想从 ListA(Login 字段是唯一键)中获取项目的列表是两个列表之间的差异。

示例:如果 ListA 中的 Login "MyLogin"，FirstName 的值与 中的值不匹配列表B。 Login 为“MyLogin”的项目必须是结果列表的一部分。

示例:如果特定登录的 ListA 和 ListB 之间的 Age 不同，则该项目必须是结果的一部分

谢谢。

Answer 1

要比较自定义数据类型列表的对象，您需要在您的类中实现IEquatable 并覆盖GetHashCode()

检查这个MSDN Link

你的类(class)

    public class PersonInfo : IEquatable<PersonInfo>
    {
        public string Login { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public int Age { get; set; }
        public bool Active { get; set; }

        public bool Equals(PersonInfo other)
        {
            //Check whether the compared object is null.
            if (Object.ReferenceEquals(other, null)) return false;

            //Check whether the compared object references the same data.
            if (Object.ReferenceEquals(this, other)) return true;

            //Check whether the properties are equal.
            return Login.Equals(other.Login) && FirstName.Equals(other.FirstName) && LastName.Equals(other.LastName) && Age.Equals(other.Age) && Active.Equals(other.Active);
        }

        public override int GetHashCode()
        {

            int hashLogin = Login == null ? 0 : Login.GetHashCode();

            int hashFirstName = FirstName == null ? 0 : FirstName.GetHashCode();

            int hashLastName = LastName == null ? 0 : LastName.GetHashCode();

            int hashAge = Age.GetHashCode();

            int hashActive = Active.GetHashCode();

            //Calculate the hash code.
            return (hashLogin + hashFirstName + hashLastName) ^ (hashAge + hashActive);
        }
    }

然后这里是你如何使用它(如 Pranay 的回复中所列)

            List<PersonInfo> ListA = new List<PersonInfo>() { new PersonInfo { Login = "1", FirstName = "James", LastName = "Watson", Active = true, Age = 21 }, new PersonInfo { Login = "2", FirstName = "Jane", LastName = "Morrison", Active = true, Age = 25 }, new PersonInfo { Login = "3", FirstName = "Kim", LastName = "John", Active = false, Age = 33 } };
            List<PersonInfo> ListB = new List<PersonInfo>() { new PersonInfo { Login = "1", FirstName = "James2222", LastName = "Watson", Active = true, Age = 21 }, new PersonInfo { Login = "3", FirstName = "Kim", LastName = "John", Active = false, Age = 33 } };

            //Get Items in ListA that are not in ListB
            List<PersonInfo> FilteredListA = ListA.Except(ListB).ToList();

            //To get the difference between ListA and FilteredListA (items from FilteredListA will be removed from ListA)
            ListA.RemoveAll(a => FilteredListA.Contains(a));