Question

我的函数接受List类型的参数，如下所示：

private decimal CalculateIRR(List<AmortizationDepotResult> lstAmortizationDepotResult, decimal carryAmount)
        {

            if (lstAmortizationDepotResult.Count > 0)
            {
                var lstLoanDepots = lstAmortizationDepotResult.ToList();
                lstLoanDepots.First().Payment = carryAmount;

在上面的代码中，我只想更改列表中第一个对象的参数值(Payment)。如果我执行上面的代码，carryAmount值会反映在lstAmortizationDepotResult以及lstLoanDepots中。但我不想更改lstAmortizationDepotResult中的值，它应仅反映在lstLoanDepots中。那我怎么解决我的问题???

谢谢..

Answer 1

欢迎来到对象世界，您的变量不是值，而是引用。因此：

var a = new Foo();
var b = a;
a.Bar = "Hello!";
Console.WriteLine(b.Bar); // output = "Hello!"

如果要将对象的值复制到另一个相同的对象，使它们不共享相同的内存空间，则必须明确地执行此操作：

var b = new Foo
 {
    Bar = a.Bar,
    OtherField = a.OtherField
 };

Answer 2

if (lstAmortizationDepotResult.Count > 0) { var lstLoanDepots = lstAmortizationDepotResult .Select(x=> new AmortizationDepotResult{ Payment = carryAmount, Property2 = x.Property2, Property3 = x.Property3, .... }) .ToList(); // ...创建一个新列表，但包含的所有对象都引用原始对象。如果需要列表中所有对象的深层副本，请提供适当的构造函数或手动初始化所有属性。

for

Answer 3

我在您的IClonable课程中实施AmortizationDepotResult界面：

public class AmortizationDepotResult ... 
  IClonable {

  ...

  Object IClonable.Clone() {
    return Clone();
  }

  public AmortizationDepotResult Clone() {
    AmortizationDepotResult result = new AmortizationDepotResult();
    ...    
    result.Payment = Payment;
    ...

    return result;
  }
}

因此，为了拥有深层复制，您可以

private decimal CalculateIRR(List<AmortizationDepotResult> lstAmortizationDepotResult, decimal carryAmount) {
  if (lstAmortizationDepotResult.Count > 0) {
    var lstLoanDepots = lstAmortizationDepotResult
      .Select(item => item.Clone())
      .ToList();

    lstLoanDepots[0].Payment = carryAmount; 
    ...
  }

与在C＃中制作List变量副本相关的问题

3 个答案: