我有一个自定义类型 ( Money
),它具有到十进制的隐式转换和+
. 当我有这些类型的列表并调用 linqSum
方法时,结果是十进制的,而不是Money
. 我怎样才能让+
运营商主持并从Sum
?
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; }
set
{
_iso3LetterCode = value.Iso3LetterCode;
_currency = value;
}
}
public Money(decimal? amount, string iso3LetterCurrencyCode)
{
Amount = amount;
Currency = Currency.FromIso3LetterCode(iso3LetterCurrencyCode);
}
public static Money operator +(Money c1, Money c2)
{
if (c1.Currency != c2.Currency)
throw new ArgumentException(string.Format("Cannot add mixed currencies {0} differs from {1}",
c1.Currency, c2.Currency));
var value = c1.Amount + c2.Amount;
return new Money(value, c1.Currency);
}
public static implicit operator decimal?(Money money)
{
return money.Amount;
}
public static implicit operator decimal(Money money)
{
return money.Amount ?? 0;
}
}