相关疑难解决方法(0)

我有一个自定义类型(Money)有一个implict转换为十进制和一个重载运算符+.当我有这些类型的列表并调用linq Sum方法时,结果是十进制,而不是Money.我如何给+运营商总统并从Sum？返回资金？

internal class Test
{
    void Example()
    {
        var list = new[] { new Money(10, "GBP"), new Money(20, "GBP") };
        //this line fails to compile as there is not implicit 
        //conversion from decimal to money
        Money result = list.Sum(x => x);
    }
}


public class Money
{
    private Currency _currency;
    private string _iso3LetterCode;

    public decimal? Amount { get; set; }
    public Currency Currency
    {
        get {  return _currency; …

首先，我按照本教程创建了我的Money对象：https : //www.codeproject.com/articles/837791/money-pattern

Money totalItems = _invoice.InvoiceDetails
    .Sum(y => y.Amount); // Amount is of type Money

我在上收到编译异常y.Amount：

无法将类型'Money'隐式转换为'long？' 无法将lambda表达式转换为预期的委托类型，因为该块中的某些返回类型不能隐式转换为委托返回类型

我究竟做错了什么？

这是我的Money课程：

public class Money
{
    public decimal Amount { get; private set; }
    public CurrencyCode Currency { get; private set; }

    #region Constructors
    public Money() { }
    public Money(Money amount)
    {
        this.Amount = amount.Amount;
        this.Currency = amount.Currency;
    }
    public Money(decimal amount, CurrencyCode currencyCode)
    {
        this.Amount = amount;
        this.Currency = currencyCode;
    }
    public Money(int amount, CurrencyCode currency)
        : …