我正在将 .NET 6 与实体框架结合使用。这是我的情况: 我有一个 BenefitEntity(具有名称和描述属性以及与 BenefitCategory 的关系),并且这个 BenefitCategory 也具有名称和描述。
在应用程序中,所有名称和描述都已翻译,我们有一个包含所有翻译的 TranslationEntities 表。
这是三个类(我会保持简单,只放置我们需要的属性):
public class BenefitEntity
{
public Guid Id { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public Guid BenefitCategoryId { get; set; }
public virtual BenefitCategoryEntity CategoryEntity { get; set; }
}
public class BenefitCategoryEntity
{
public Guid Id { get; set; }
public string Name { get; set; }
public string Description { get; set; }
}
public class TranslationEntity
{
public Guid EntityId { get; set; }
public string Language { get; set; }
public string Property { get; set; }
public string Value { get; set; }
}
TranslationEntities 表包含所有实体类型的所有翻译。我想获取所有 BenefitEntity,使用 GroupJoin 作为其名称/描述,并为其 BenefitCategory 名称和描述执行另一个内部联接。我可以做第一个,但做不到第二个。
这就是我所做的:
public async Task<ICollection<BenefitEntity>> GetAllBenefitEntitiesAsync()
{
var benefitsQuery = Entities
.Include(a => a.CategoryEntity);
var translationsQuery = DbContext.TranslationsEntities!
.AsNoTracking()
.Where(e => e.Language.Equals(LANGUAGE));
var benefits = await benefitsQuery.ToListAsync();
var result = benefits
.GroupJoin(
translationsQuery,
benefit => benefit.Id,
translation => translation.EntityId,
(benefit, translation) => new { Benefit = benefit, Translation = translation })
.Select(result => new BenefitEntity
{
// Benefit Name and Description from joined translations
Name = result.Translation.FirstOrDefault(e => e.Property.Equals(nameof(BenefitEntity.Name)))?.Value ?? result.Benefit.Name,
Description = result.Translation.FirstOrDefault(e => e.Property.Equals(nameof(BenefitEntity.Description)))?.Value ?? result.Benefit.Description,
Id = result.Benefit.Id,
CategoryEntity = result.Benefit.CategoryEntity,
BenefitCategoryId = result.Benefit.BenefitCategoryId,
})
.AsQueryable();
return result.ToList();
}
从这一点开始,我如何使用相同的translationQuery,将categoryEntity.Id与translation.EntityId连接起来,对CategoryEntity进行另一个Join?
在此更新的代码中:
添加了一个新的选择,将翻译具体化到列表中以供多种使用。 新属性 CategoryName 和 CategoryDescription 已添加到 BenefitEntity 以保存 BenefitCategoryEntity 的翻译值。 BenefitCategoryEntity.Name 和 BenefitCategoryEntity.Description 的翻译值是使用相同的翻译逻辑获取的。
public async Task<ICollection<BenefitEntity>> GetAllBenefitEntitiesAsync() { var benefitsQuery = Entities .Include(a => a.CategoryEntity);
var translationsQuery = DbContext.TranslationsEntities!
.AsNoTracking()
.Where(e => e.Language.Equals(LANGUAGE));
var benefits = await benefitsQuery.ToListAsync();
var result = benefits
.GroupJoin(
translationsQuery,
benefit => benefit.Id,
translation => translation.EntityId,
(benefit, translation) => new { Benefit = benefit, Translation = translation })
.Select(result => new
{
Benefit = result.Benefit,
Translation = result.Translation.ToList()
})
.Select(result => new BenefitEntity
{
// Benefit Name and Description from joined translations
Name = result.Translation.FirstOrDefault(e => e.Property.Equals(nameof(BenefitEntity.Name)))?.Value ?? result.Benefit.Name,
Description = result.Translation.FirstOrDefault(e => e.Property.Equals(nameof(BenefitEntity.Description)))?.Value ?? result.Benefit.Description,
Id = result.Benefit.Id,
CategoryEntity = result.Benefit.CategoryEntity,
BenefitCategoryId = result.Benefit.BenefitCategoryId,
CategoryName = result.Translation.FirstOrDefault(e => e.Property.Equals(nameof(BenefitCategoryEntity.Name)))?.Value ?? result.Benefit.CategoryEntity.Name,
CategoryDescription = result.Translation.FirstOrDefault(e => e.Property.Equals(nameof(BenefitCategoryEntity.Description)))?.Value ?? result.Benefit.CategoryEntity.Description
})
.AsQueryable();`enter code here`
return result.ToList();
}