ListComparer

ListComparer.cs

using System;
using System.Collections.Generic;
using System.Linq;

/// <summary>
/// 物料代码实体。
/// </summary>
public class EntMaterielCodes
{
    public string? RFIDCode { get; set; }
    public string? UniqueCode { get; set; }

    public override string ToString()
    {
        return $"[RFID: {RFIDCode ?? "N/A"}, UniqueCode: {UniqueCode ?? "N/A"}]";
    }
}

/// <summary>
/// 用于比较 EntMaterielCodes 对象的相等性和哈希码。
/// </summary>
public class MaterielCodesComparer : IEqualityComparer<EntMaterielCodes>
{
    /// <summary>
    /// 检查两个 EntMaterielCodes 实例是否基于它们的 RFIDCode 和 UniqueCode 字段相等。
    /// </summary>
    public bool Equals(EntMaterielCodes? x, EntMaterielCodes? y)
    {
        if (Object.ReferenceEquals(x, y)) return true;
        if (x is null || y is null) return false;

        // 使用 Ordinal 比较字符串，确保比较的确定性和性能。
        return StringComparer.Ordinal.Equals(x.RFIDCode, y.RFIDCode) &&
               StringComparer.Ordinal.Equals(x.UniqueCode, y.UniqueCode);
    }

    /// <summary>
    /// 基于 RFIDCode 和 UniqueCode 计算对象的哈希码。
    /// </summary>
    public int GetHashCode(EntMaterielCodes obj)
    {
        if (obj is null) return 0;
        
        // 使用 ValueTuple 的 GetHashCode 方法结合两个属性生成哈希码。
        return (obj.RFIDCode, obj.UniqueCode).GetHashCode();
    }
}

// 假设这些是您的源数据结构
public class SourceCodeEntity
{
    public string? RFIDCode { get; set; }
    public string? UniqueCode { get; set; }
}

public class NewCodeEntity
{
    public string? RFID { get; set; }
    public string? UniqueCode { get; set; }
}


public class Sample
{
    private readonly IEnumerable<SourceCodeEntity> codes = new List<SourceCodeEntity>
    {
        new SourceCodeEntity { RFIDCode = "A1", UniqueCode = "U1" },
        new SourceCodeEntity { RFIDCode = "B2", UniqueCode = "U2" },
        new SourceCodeEntity { RFIDCode = "C3", UniqueCode = "U3" }
    };
    
    private readonly IEnumerable<NewCodeEntity> newCodes = new List<NewCodeEntity>
    {
        new NewCodeEntity { RFID = "C3", UniqueCode = "U3" },
        new NewCodeEntity { RFID = "D4", UniqueCode = "U4" },
        new NewCodeEntity { RFID = "E5", UniqueCode = "U5" }
    };

    private void Run()
    {
        // 以前的码（旧库存）投影
        var oldCodesProjection = codes
            .Select(x => new EntMaterielCodes { RFIDCode = x.RFIDCode, UniqueCode = x.UniqueCode });
        
        // 当前传入的码（新盘点/传入）投影
        var newCodesProjection = newCodes
            .Select(x => new EntMaterielCodes { RFIDCode = x.RFID, UniqueCode = x.UniqueCode }); 

        var comparer = new MaterielCodesComparer();

        // 将旧集合转换为 HashSet 以提高 Except 和 Intersect 的查找性能
        var oldSet = oldCodesProjection.ToHashSet(comparer);
        
        // 亏 (Deficit): 在旧集合中，但不在新集合中
        var deficitList = oldSet
            .Except(newCodesProjection, comparer)
            .ToList(); 

        // 盈 (Surplus): 在新集合中，但不在旧集合中
        var surplusList = newCodesProjection
            .Except(oldSet, comparer)
            .ToList();

        // 正常 (Normal): 新旧集合的交集
        var intersectList = newCodesProjection
            .Intersect(oldSet, comparer)
            .ToList();
            
        Console.WriteLine($"--- 亏损项 ---");
        deficitList.ForEach(c => Console.WriteLine(c));
        
        Console.WriteLine($"\n--- 盈余项 ---");
        surplusList.ForEach(c => Console.WriteLine(c));
        
        Console.WriteLine($"\n--- 正常项 ---");
        intersectList.ForEach(c => Console.WriteLine(c));
    }
    
    public static void Main(string[] args)
    {
        new Sample().Run();
    }
}