C# 将列表中某项的属性值推送到该列表中的下一项

我有两个对象，比如Amount，NewAmount，它们都有下面的属性

public class Amount
{
    public Int64 Id { get; set; }
    public Int64 Amt1 { get; set; }
    public Int64 Amt2 { get; set; }
} 
public class NewAmountDo
{
   public Int64 newAmt { get; set; }
}

我有一个包含一些值的Amount列表和一个包含一个值的NewAmount对象

List<Amount> amountListObject = new List<Amount>();
Amount amount = new Amount();
Amount amount1 = new Amount();
Amount amount2 = new Amount();
Amount amount3 = new Amount();
NewAmountDo newAmountDo = new NewAmountDo();
newAmountDo.newAmt = 50;
amount.Id = 1;
amount.Amt1 = 10;
amount.Amt2 = 100;
amountListObject.Add(amount);
amount1.Id = 2;
amount1.Amt1 = 20;
amount1.Amt2 = 200;
amountListObject.Add(amount1);
amount2.Id = 0;
amount2.Amt1 = 30;
amount2.Amt2 = 300;
amountListObject.Add(amount2);
amount3.Id = 0;
amount3.Amt1 = 40;
amount3.Amt2 = 400;
amountListObject.Add(amount3);

Console.WriteLine("Input ");
exising = amountListObject;

List<Amount> intermediate = new List<Amount>();
Amount newamount = new Amount();
intermediate.AddRange(amountListObject);
intermediate.Add(newamount);

下面是我得到的结果

Id : 1 , Amt1 : 50 , Amt2 : 100 
Id : 2 , Amt1 : 50 , Amt2 : 200
Id : 0 , Amt1 : 50 , Amt2 : 300
Id : 0 , Amt1 : 50 , Amt2 : 400
Id : 0 , Amt1 : 50 , Amt2 : 0

预期结果：

Id : 1 , Amt1 : 50 , Amt2 : 100
Id : 2 , Amt1 : 10 , Amt2 : 200
Id : 0 , Amt1 : 20 , Amt2 : 300
Id : 0 , Amt1 : 30 , Amt2 : 400
Id : 0 , Amt1 : 40, Amt2 : 0

---

有什么办法可以做到这一点吗？

问题是您在两个列表之间复制了Amount对象的引用。因此，当您将金额从上一个元素复制到中间列表时，基本上覆盖了将在下一个循环中使用的值

我看到了3种解决您问题的方法：

对于您的金额类型，请使用结构而不是类。这将执行值复制，而不是引用复制，因此两个列表中不会有相同的实例，也不会有任何冲突

如果您确实需要将您的类型设置为类，则可以执行复制构造函数并复制中间列表中的项，如下所示：

intermediate.AddRange(amountListObject.Select(o => new Amount(o)));

Int64 previous;
for (int i = 0; i < intermediate.Count; i++)
{
    if (i == 0)
    {
        previous = intermediate[i].Amt1;
        intermediate[i].Amt1 = newAmountDo.newAmt;
    }
    else
    {
        Int64 temp = intermediate[i].Amt1;
        intermediate[i].Amt1 = previous;
        previous = temp;
    }
}

这样，列表中仍然会有引用，但每个引用都会指向类型Amount的不同实例，因此不会发生冲突

如果要避免对象的任何副本，则需要修改代码，以便在foreach中使用中间值来保留以前的值，如下所示：

intermediate.AddRange(amountListObject.Select(o => new Amount(o)));

Int64 previous;
for (int i = 0; i < intermediate.Count; i++)
{
    if (i == 0)
    {
        previous = intermediate[i].Amt1;
        intermediate[i].Amt1 = newAmountDo.newAmt;
    }
    else
    {
        Int64 temp = intermediate[i].Amt1;
        intermediate[i].Amt1 = previous;
        previous = temp;
    }
}

Int64先前版本；
for（int i=0；i

---

首先为定义的类声明构造函数，它将有助于初始化，并为代码提供更好的可读性

public class Amount
    {
        public Int64 Id { get; set; }
        public Int64 Amt1 { get; set; }
        public Int64 Amt2 { get; set; }

        public Amount(Int64 Id, Int64 Amt1, Int64 Amt2)
        {
            this.Id = Id;
            this.Amt1 = Amt1;
            this.Amt2 = Amt2;
        }
    }
    public class NewAmountDo
    {
        public Int64 newAmt { get; set; }

        public NewAmountDo(Int64 newAmt)
        {
            this.newAmt = newAmt;
        }
    }

现在，初始化将更加干净：

List<Amount> amountListObject = new List<Amount>();

Amount amount = new Amount(1,10,100);
Amount amount1 = new Amount(2,20,200);
Amount amount2 = new Amount(0,30,300);
Amount amount3 = new Amount(0,40,400);
NewAmountDo newAmount = new NewAmountDo(50);
amountListObject = new List<Amount>() { amount, amount1, amount2, amount3 };

List amountListObject=new List（）；
金额=新金额（1,10100）；
金额1=新金额（2,20200）；
金额2=新金额（0,30300）；
金额3=新金额（0,40400）；
NewAmountDo newAmount=新的NewAmountDo（50）；
amountListObject=new List（）{amount，amount1，amount2，amount3}；

现在问题解决了：

Int64 shiftedAmt = 0;
        for (int i = 0; i < amountListObject.Count; i++)
        {                
            /* First element in the list */
            if (i == 0)
            {
                /* save the amt1 property value for shifting */
                shiftedAmt = amountListObject[i].Amt1;
                /* Switch to the new amount (if you need to add the new to the old just replace with +=) */
                amountListObject[i].Amt1 = newAmount.newAmt;
            }
            else
            {
                /* Shift the value */
                Int64 temp = amountListObject[i].Amt1;
                amountListObject[i].Amt1 = shiftedAmt;
                shiftedAmt = temp;
            }
        }
        /* Create new Amount object for the last shifted amt1 value */
        Amount _amount = new Amount(0, shiftedAmt, 0);
        amountListObject.Add(_amount);

Int64移位金额=0；
for（int i=0；i