无法将运算符“&&”应用于 'bool' 和 'Fuel.LoanPayments.LoanPayment' 类型的操作数

Question

我尝试用前置条件编写映射器

这是代码

configuration.CreateMap<Loan, LoanDto>()
    .ForMember(x=> x.NextPaymentAmount, opt =>
    {
        opt.PreCondition(
            src => (src.DirectDebitCollection.Count > 0) &&
                   (src.LoanPayments
                       .FirstOrDefault(x => 
                           x.LoanPaymentStatusId == (int)LoanPaymentStatusEnum.Due)));
                
                opt.MapFrom(src=> src.DirectDebitCollection);
    });

但是在这一行 opt.PreCondition(src => (src.DirectDebitCollection.Count > 0) && (src.LoanPayments.FirstOrDefault(x=> x.LoanPaymentStatusId == (int)LoanPaymentStatusEnum.Due)));

我遇到了这个错误

Cannot apply operator '&&' to operands of type 'bool' and 'Fuel.LoanPayments.LoanPayment'

我需要如何重写它？

Answer 1

是因为

(src.LoanPayments
    .FirstOrDefault(x => x.LoanPaymentStatusId == (int)LoanPaymentStatusEnum.Due))

returns 列表中的一项

如果你使用

(src.LoanPayments
    .Any(x => x.LoanPaymentStatusId == (int)LoanPaymentStatusEnum.Due)))

它会 return 如果列表中存在一个项目则为真，如果列表中不存在则为假

无法将运算符“&&”应用于 'bool' 和 'Fuel.LoanPayments.LoanPayment' 类型的操作数

Cannot apply operator '&&' to operands of type 'bool' and 'Fuel.LoanPayments.LoanPayment'

c#

asp.net

automapper

asp.net-core