从对象列表中的列表中获取值C#

Question

我有一个 class object(obj1) 的 List，并且该类包含另一个 List 的另一个 class object(obj2)。以下是我的代码：

public List<Class1> Obj1{ get; set; }

 public class Class1
    {
        [DataMember]
        public int Class1Id { get; set; }
        [DataMember]
        public string Class1Desc { get; set; }
        [DataMember]
        public List<Class2> obj2{ get; set; }
    }

public class Class2
    {
        [DataMember]
        public int Class2Id { get; set; }
        [DataMember]
        public string Class2Desc { get; set; }
    }

现在，我需要填充变量以确保不会得到重复值（即 Class1Id 和 Class2Id 的组合应该是唯一的）。

我不想使用循环。我怎样才能做到这一点？

Answer 1

使用IEquatable，然后使用Distinct()：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;

namespace ConsoleApplication52
{
    class Program
    {
        static void Main(string[] args)
        {
            List<Class1> Obj1 = new List<Class1> {
                new Class1() { Class1Desc = "A", Class1Id = 1, obj2 = new List<Class2>() { new Class2() { Class2Id = 100, Class2Desc= "M"}}},
                new Class1() { Class1Desc = "B", Class1Id = 1, obj2 = new List<Class2>() { new Class2() { Class2Id = 100, Class2Desc= "M"}}},
                new Class1() { Class1Desc = "A", Class1Id = 1, obj2 = new List<Class2>() { new Class2() { Class2Id = 100, Class2Desc= "M"}}},
                new Class1() { Class1Desc = "A", Class1Id = 1, obj2 = new List<Class2>() { new Class2() { Class2Id = 200, Class2Desc= "M"}}}
            };

            List<Class1> distinctClass1 = Obj1.Distinct().ToList();
        }
    }
    public class Class1 : IEquatable<Class1>
    {
        public int Class1Id { get; set; }
        public string Class1Desc { get; set; }
        public List<Class2> obj2 { get; set; }

        public Boolean Equals(Class1 other)
        {

            if (other == null) return false;
            if ((this.Class1Id == other.Class1Id) && (this.Class1Desc == other.Class1Desc) && (this.obj2.OrderBy(x => x).SequenceEqual(other.obj2.OrderBy(x => x))))
            {
                return true;
            }
            else
            {
                return false;
            }
        }
        public override int GetHashCode()
        {
            return (this.Class1Id.ToString() + "^" + this.Class1Desc + string.Join("^", obj2.Select(x => x.GetHashCodeStr()))).GetHashCode();
        }

    }

    public class Class2 : IEquatable<Class2> , IComparer<Class2>
    {
        public int Class2Id { get; set; }
        public string Class2Desc { get; set; }

        public Boolean Equals(Class2 other)
        {
            if(other == null) return false;
            if ((this.Class2Id == other.Class2Id) && (this.Class2Desc == other.Class2Desc))
            {
                return true;
            }
            else
            {
                return false;
            }
        }
        public int Compare(Class2 x, Class2 y)
        {
            int results = 0;
            results = x.Class2Id.CompareTo(y.Class2Id);
            if (results == 0)
            {
                results = x.Class2Desc.CompareTo(y.Class2Desc);
            }
            return results;
        }
        public override int GetHashCode()
        {
            return (this.Class2Id.ToString() + "^" + this.Class2Desc).GetHashCode();
        }
        public string GetHashCodeStr()
        {
            return this.Class2Id.ToString() + "^" + this.Class2Desc;
        }

    }
}