List <>集合成员在不应该更改时更改

Question

我有一个List,我已经在控制台项目的main方法中填充了.我这一人群传递给其目的是要采取人口的两名成员和分解的方式来创建稍后将加入人口两个新的唯一成员重新组合它们的方法.

然而,当我操纵两个原始成员来创建两个新的独特成员时,两个原始成员在初始人口中改变(因此改变了初始人口).这意味着当我去添加新成员时,我得到重复的条目列表.

我没有做任何过于复杂的事情我认为我只是在做一些愚蠢的事情.

有没有人知道为什么会这样？

以下是调用以选择初始化两个人口成员的方法:

public static List<Chromosome<Gene>> runEpoch(Random rand, List<Chromosome<Gene>> population, SelectionMethod selectionMethod)
    {
        int populationSize = population.Count;
        int selectionCount = (int)Math.Truncate((population.Count * 0.75));

        if (selectionMethod == SelectionMethod.Tournament)
        {
            for (int i = 0; i < selectionCount; i++)
            {
                Chromosome<Gene> parent = selection.runTournament(rand, population);
                Chromosome<Gene> parentTwo = selection.runTournament(rand, population);

                //Checks for the presence of incestuous mating. In some cases incestuous mating causes a stack overflow to occur that the program can not recover from 
                if (parent != parentTwo)
                {
                    //where runGeneOperators calls the crossOver method directly
                    offSpring = runGeneOperators(rand, parent, parentTwo);
                }
                else
                {
                    i--;
                }
            }
        }
        else
        {
            //NSGAII
        }
        //fixPopulation is meant to sort and remove any excess members
        return fixPopulation(rand, population, selectionMethod, populationSize); ;
    }

以下是创建两个新的唯一成员的代码:

public List<Chromosome<Gene>> crossOver(Random rand, Chromosome<Gene> parentOne, Chromosome<Gene> parentTwo)
    {
        List<Chromosome<Gene>> offSpring = new List<Chromosome<Gene>>();

        int crossPtOne = rand.Next(0, parentOne.Length);
        int crossPtTwo = rand.Next(0, parentTwo.Length);

        if ((crossPtOne == 0) && (crossPtTwo == 0))
        {
            offSpring.Add(parentOne);
            offSpring.Add(parentTwo);

            return offSpring;
        }
        else
        {
            GeneNode<Gene> fragOne = parentOne.Children[crossPtOne];
            GeneNode<Gene> fragTwo = parentTwo.Children[crossPtTwo];

            crossOverPoint = crossPtOne;
            GeneNode<Gene> genotype = performCrossOver(parentOne.Genotype, fragTwo);
            success = false;

            parentOne.repair(genotype);

            offSpring.Add(parentOne);

            crossOverPoint = crossPtTwo;

            GeneNode<Gene> genotype2 = performCrossOver(parentTwo.Genotype, fragOne);
            success = false;

            parentTwo.repair(genotype2);

            offSpring.Add(parentTwo);
        }

        return offSpring;
    }

    private GeneNode<Gene> performCrossOver(GeneNode<Gene> tree, GeneNode<Gene> frag)
    {
        if (tree != null)
        {
            if (crossOverPoint > 0)
            {
                if (!success && tree.Left != null)
                {
                    crossOverPoint--;
                    tree.Children[0] = performCrossOver(tree.Left, frag);
                }
            }

            if (crossOverPoint > 0)
            {
                if (!success && tree.Right != null)
                {
                    crossOverPoint--;
                    tree.Children[1] = performCrossOver(tree.Right, frag);
                }
            }
        }

        if (!success)
        {
            if (crossOverPoint == 0)
            {
                success = true;
                return frag;
            }
        }

        return tree;
    }

Answer 1

在C#中,对象是引用类型,这意味着向集合添加内容只会添加引用.如果使用相同的引用(在您的情况下,"原始"对象)操作变量,则指向该对象的所有引用也将更改.您需要以某种方式复制对象以拥有不同的对象并对其进行操作.