[英]Ef core many to many relationship inside a generic repository
我正在嘗試在我的 Web 應用程序中使用多對多關系。 我正在使用通用存儲庫基本代碼。
這是我的實體
public class UserEntity : BaseEntity<int>
{
public string EmployeeId { get; set; }
public string FullName { get; set; }
public string Email { get; set; }
public virtual ICollection<UserRoleEntity> UserRoles { get; set; }
}
public class RoleEntity : BaseEntity<int>
{
public string Name { get; set; }
public virtual ICollection<UserRoleEntity> Users { get; set; }
}
public class UserRoleEntity : BaseEntity<Guid>
{
public int UserId { get; set; }
public int RoleId { get; set; }
public virtual UserEntity UserEntity { get; set; }
public virtual RoleEntity RoleEntity { get; set; }
}
這是上下文模型配置
private void ConfigureUserRole(EntityTypeBuilder<UserRoleEntity> builder)
{
builder.ToTable("UserRole");
//there is no need for a surrogate key on many-to-many mapping table
builder.Ignore("Id");
builder.HasKey(ur => new { ur.RoleId, ur.UserId });
builder.HasOne(ur => ur.RoleEntity)
.WithMany(r => r.Users)
.HasForeignKey(ur => ur.RoleId);
builder.HasOne(ur => ur.UserEntity)
.WithMany(u => u.UserRoles)
.HasForeignKey(ur => ur.UserId);
}
這是我的通用存儲庫的主要 get 方法(實際上它是Chris Pratt的實現)請注意query.Include
行,通用存儲庫的 get 方法利用 EF Core 的Include
api 來獲取以字符串形式出現的依賴實體范圍 。
protected virtual IQueryable<T> GetQueryable(Expression<Func<T, bool>> filter = null, Func<IQueryable<T>, IOrderedQueryable<T>> orderBy = null,
string includeProperties = null,
int? skip = null,
int? take = null)
{
includeProperties = includeProperties ?? string.Empty;
IQueryable<T> query = _dbContext.Set<T>();
if (filter != null)
{
query = query.Where(filter);
}
foreach (var includeProperty in includeProperties.Split
(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries))
{
query = query.Include(includeProperty);
}
if (orderBy != null)
{
query = orderBy(query);
}
if (skip.HasValue)
{
query = query.Skip(skip.Value);
}
if (take.HasValue)
{
query = query.Take(take.Value);
}
return query;
}
在我的服務中,我想獲取用戶數據及其完整的依賴項。
public class UserService : IUserService
{
private IRepository<UserEntity> _userRepository;
private IRepository<RoleEntity> _roleRepository;
public UserService(IRepository<UserEntity> userRepository, IRepository<RoleEntity> roleRepository)
{
_userRepository = userRepository;
_roleRepository = roleRepository;
}
public UserEntity GetUserData(string employeeId)
{
var user = _userRepository.GetFirst(u => u.EmployeeId == employeeId, includeProperties: "UserRoles");
//var roles = _roleRepository.GetAll().ToList();
return user;
}
}
當上面的服務代碼執行時,我得到用戶依賴它的UserRole
,但是,當我檢查我需要的UserRole
的RoleEntity
依賴時,它是null
。
如何僅通過修改通用存儲庫的 get 方法來獲取依賴的RoleEntity
數據?
其次,服務代碼中注釋的行( _roleRepository.GetAll()
),當它也被執行時, RoleEntity
會立即填充其正確的值。 它是如何發生的?
您的包含路徑只有從UserEntity
到UserRoleEntity
的單跳(通過UserRoles
屬性。您需要包含下一步以確保您也捕獲RoleEntity
。為此,請將您的路徑更改為UserRoles.RoleEntity
,例如:
var user = _userRepository.GetFirst(
u => u.EmployeeId == employeeId,
includeProperties: "UserRoles.RoleEntity");
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