Question

我有一个ProductForReturnDTO，我希望从Product模型中进行映射。在映射过程中，我想从称为AverageRating的方法映射"CalculateAverageRating"。此方法将基于ProductReview集合中的总记录计算平均评分。

但是我得到了错误：

当试图在映射中包括此方法时，“ ICollection”不包含“ CalculateAverageRating”的定义，并且没有可访问的扩展方法“ CalculateAverageRating””。

有人可以建议我吗？

产品型号

public class Product
{
    public int Id { get; set; }
    public string Name { get; set; }

    public ICollection<ProductReview> ProductReviews { get; set; }

    public Product() 
    {
        ProductReviews = new Collection<ProductReview>();
    }
}

ProductForReturnDTO

public class ProductForReturnDto
{
    public int Id { get; set; }
    public string Name { get; set; }

    public int AverageRating { get; set; }

    public ICollection<ProductReviewForReturnDto> ProductReviews { get; set; }
}

产品评论模型

public class ProductReview
{
    public int Id { get; set; }
    public int Rating { get; set; }
    public string Review { get; set; }

    public Product Product { get; set; }
    public int ProductId { get; set; }

}

CalculateAverageRating

public static class Extensions
{
    public static int CalculateAverageRating(this ICollection<ProductReview> productReviews)
    {
        var totalReviews = productReviews.Count;

        var totalRatings = productReviews.Sum(pr => pr.Rating);

        var maxRatings = totalReviews * 5;

        int averageRatings = (totalRatings / maxRatings) * 5;

        return averageRatings;
    }
}

映射器配置文件

public ProductProfiles()
    {            
        CreateMap<Product, ProductForReturnDto>()
            .ForMember(dest => dest.AverageRating, opt => {
                opt.MapFrom(d => d.ProductReviews.CalculateAverageRating());
            });
    }

AutoMapper使用方法从源映射值

0 个答案: