Question

我想使用AutoMapper将三个表的数据转换为平面ViewModel。

由于我不知道如何设置必要的AutoMapper配置，因此，感谢您提供有关如何解决此问题的信息。

   extension UIButton {
    func addRightImage(image: UIImage, offset: CGFloat) {
        self.setImage(image, for: .normal)
        self.imageView?.translatesAutoresizingMaskIntoConstraints = false
        self.imageView?.centerYAnchor.constraint(equalTo: self.centerYAnchor, constant: 0.0).isActive = true
        self.imageView?.trailingAnchor.constraint(equalTo: self.trailingAnchor, constant: -offset).isActive = true
    }
}

我的视图模型：

public class Category {
    public int Id { get; set; }
    public string Title { get; set; }
    public string Description { get; set; }
    public virtual ICollection<BankingAccountCategory> BankingAccountCategories { get; set; }
}

public class BankingAccountCategory {
    public int Id { get; set; }
    public int BankingAccountId { get; set; }
    public int CategoryId { get; set; }
    public virtual BankingAccount BankingAccount { get; set; }
    public virtual Category Category { get; set; }
    public virtual ICollection<Expense> Expenses { get; set; }
}

public class Expense {
    public int Id { get; set; }
    public int BankingAccountCategoryId { get; set; }
    public DateTime Date { get; set; }
    public decimal Amount { get; set; }
    public virtual BankingAccountCategory BankingAccountCategory { get; set; }
}

在sql方面，此查询提供了我想要的结果：

public class CategoryViewModel {
    public int Id { get; set; }
    public string Title { get; set; }
    public string Description { get; set; }
    public int NumberOfExpenses { get; set; }
}

我的自动映射器配置：

select cat.Id, cat.Title, cat.Description, count(ex.Id) as ExpenseCount from Category cat
  inner join BankingAccountCategory bac on bac.CategoryId = cat.Id                 
  left outer join Expense ex on ex.BankingAccountCategoryId = bac.Id
  group by cat.Id, cat.Title, cat.Description

问题在于，所有条目的NumberOfExpenses始终为0。

Answer 1

您的原始配置将返回IEnumerable<ICollection<Expense>>，而不是所需的int。

尝试以下方法：

CreateMap<Category, CategoryViewModel>()
    .ForMember(dest => dest.NumberOfExpenses,
        opt => opt.MapFrom(cat => BankingAccountCategories.Sum(bac => bac.Expenses.Count())));

AutoMapper：子实体数

1 个答案: