我正在修改我的应用程序，以便能够指定要在存储库中加载的导航属性。
型号：Team和TeamTunerUser可以在domain entites找到。
库：
namespace Sppd.TeamTuner.Infrastructure.DataAccess.EF.Repositories
{
internal class Repository<TEntity> : IRepository<TEntity>
where TEntity : BaseEntity
{
/// <summary>
/// Gets the entity set.
/// </summary>
protected DbSet<TEntity> Set => Context.Set<TEntity>();
/// <summary>
/// Gets the DB context.
/// </summary>
protected TeamTunerContext Context { get; }
public Repository(TeamTunerContext context)
{
Context = context;
}
public async Task<TEntity> GetAsync(Guid entityId, IEnumerable<string> includeProperties = null)
{
TEntity entity;
try
{
entity = await GetQueryableWithIncludes(includeProperties).SingleAsync(e => e.Id == entityId);
}
catch (InvalidOperationException)
{
throw new EntityNotFoundException(typeof(TEntity), entityId.ToString());
}
return entity;
}
protected IQueryable<TEntity> GetQueryableWithIncludes(IEnumerable<string> includeProperties = null)
{
var queryable = Set;
if (includeProperties == null)
{
return queryable;
}
foreach (var propertyName in includeProperties)
{
queryable.Include(propertyName);
}
return queryable;
}
}
}
测试：
[Fact]
public async Task TestNavigationPropertyLoading()
{
// Arrange
var teamId = Guid.Parse(TestingConstants.Team.HOLY_COW);
// Act
Team createdTeamWithoutUsers;
Team createdTeamWithUsers;
using (var scope = ServiceProvider.CreateScope())
{
var teamRepository = scope.ServiceProvider.GetService<IRepository<Team>>();
createdTeamWithoutUsers = await teamRepository.GetAsync(teamId);
createdTeamWithUsers = await teamRepository.GetAsync(teamId, new[] {nameof(Team.Users)});
}
// Assert
Assert.Null(createdTeamWithoutUsers.Leader);
Assert.False(createdTeamWithoutUsers.Users.Any());
Assert.False(createdTeamWithUsers.CoLeaders.Any());
Assert.NotNull(createdTeamWithUsers.Leader);
Assert.True(createdTeamWithUsers.Users.Any());
Assert.True(createdTeamWithUsers.CoLeaders.Any());
}
我的问题是Users导航属性永远不会被加载，第二个断言块失败。
团队配置在这里（class）：
private static void ConfigureTeam(EntityTypeBuilder<Team> builder)
{
ConfigureDescriptiveEntity(builder);
builder.HasMany(e => e.Users)
.WithOne(e => e.Team);
// Ignore calculated properties
builder.Ignore(e => e.Members)
.Ignore(e => e.Leader)
.Ignore(e => e.CoLeaders);
}
（调试）日志不包含任何有用的东西，只是我看到加载导航属性所需的连接没有在SQL级别上执行：
2019-04-11 16:02:43,896 [14] DEBUG Microsoft.EntityFrameworkCore.Database.Connection - Opening connection to database 'Sppd.TeamTuner-TEST' on server '.\SQLEXPRESS'.
2019-04-11 16:02:43,901 [14] DEBUG Microsoft.EntityFrameworkCore.Database.Connection - Opened connection to database 'Sppd.TeamTuner-TEST' on server '.\SQLEXPRESS'.
2019-04-11 16:02:43,903 [14] DEBUG Microsoft.EntityFrameworkCore.Database.Command - Executing DbCommand [Parameters=[@__entityId_0='?' (DbType = Guid)], CommandType='Text', CommandTimeout='30']
SELECT TOP(2) [m].[Id], [m].[Avatar], [m].[CreatedById], [m].[CreatedOnUtc], [m].[DeletedById], [m].[DeletedOnUtc], [m].[Description], [m].[FederationId], [m].[IsDeleted], [m].[ModifiedById], [m].[ModifiedOnUtc], [m].[Name]
FROM [Team] AS [m]
WHERE ([m].[IsDeleted] = 0) AND ([m].[Id] = @__entityId_0)
2019-04-11 16:02:43,920 [12] INFO Microsoft.EntityFrameworkCore.Database.Command - Executed DbCommand (16ms) [Parameters=[@__entityId_0='?' (DbType = Guid)], CommandType='Text', CommandTimeout='30']
SELECT TOP(2) [m].[Id], [m].[Avatar], [m].[CreatedById], [m].[CreatedOnUtc], [m].[DeletedById], [m].[DeletedOnUtc], [m].[Description], [m].[FederationId], [m].[IsDeleted], [m].[ModifiedById], [m].[ModifiedOnUtc], [m].[Name]
FROM [Team] AS [m]
WHERE ([m].[IsDeleted] = 0) AND ([m].[Id] = @__entityId_0)
2019-04-11 16:02:43,945 [12] DEBUG Microsoft.EntityFrameworkCore.Database.Command - A data reader was disposed.
2019-04-11 16:02:43,985 [12] DEBUG Microsoft.EntityFrameworkCore.Database.Connection - Closing connection to database 'Sppd.TeamTuner-TEST' on server '.\SQLEXPRESS'.
2019-04-11 16:02:43,988 [12] DEBUG Microsoft.EntityFrameworkCore.Database.Connection - Closed connection to database 'Sppd.TeamTuner-TEST' on server '.\SQLEXPRESS'.
2019-04-11 16:02:45,054 [12] DEBUG Microsoft.EntityFrameworkCore.Database.Connection - Opening connection to database 'Sppd.TeamTuner-TEST' on server '.\SQLEXPRESS'.
2019-04-11 16:02:45,057 [12] DEBUG Microsoft.EntityFrameworkCore.Database.Connection - Opened connection to database 'Sppd.TeamTuner-TEST' on server '.\SQLEXPRESS'.
2019-04-11 16:02:45,060 [12] DEBUG Microsoft.EntityFrameworkCore.Database.Command - Executing DbCommand [Parameters=[@__entityId_0='?' (DbType = Guid)], CommandType='Text', CommandTimeout='30']
SELECT TOP(2) [m].[Id], [m].[Avatar], [m].[CreatedById], [m].[CreatedOnUtc], [m].[DeletedById], [m].[DeletedOnUtc], [m].[Description], [m].[FederationId], [m].[IsDeleted], [m].[ModifiedById], [m].[ModifiedOnUtc], [m].[Name]
FROM [Team] AS [m]
WHERE ([m].[IsDeleted] = 0) AND ([m].[Id] = @__entityId_0)
2019-04-11 16:02:45,067 [14] INFO Microsoft.EntityFrameworkCore.Database.Command - Executed DbCommand (7ms) [Parameters=[@__entityId_0='?' (DbType = Guid)], CommandType='Text', CommandTimeout='30']
SELECT TOP(2) [m].[Id], [m].[Avatar], [m].[CreatedById], [m].[CreatedOnUtc], [m].[DeletedById], [m].[DeletedOnUtc], [m].[Description], [m].[FederationId], [m].[IsDeleted], [m].[ModifiedById], [m].[ModifiedOnUtc], [m].[Name]
FROM [Team] AS [m]
WHERE ([m].[IsDeleted] = 0) AND ([m].[Id] = @__entityId_0)
2019-04-11 16:02:45,092 [14] DEBUG Microsoft.EntityFrameworkCore.Database.Command - A data reader was disposed.
2019-04-11 16:02:45,143 [14] DEBUG Microsoft.EntityFrameworkCore.Database.Connection - Closing connection to database 'Sppd.TeamTuner-TEST' on server '.\SQLEXPRESS'.
2019-04-11 16:02:45,153 [14] DEBUG Microsoft.EntityFrameworkCore.Database.Connection - Closed connection to database 'Sppd.TeamTuner-TEST' on server '.\SQLEXPRESS'.
我尝试过的：
protected IQueryable<TEntity> GetQueryableWithIncludes(IEnumerable<string> includeProperties = null)
{
var queryable = Set;
if (includeProperties == null)
{
return queryable;
}
if (typeof(TEntity) == typeof(Team))
{
// TODO: Remove this block once it works by including by string properties
foreach (var propertyName in includeProperties)
{
if (propertyName == "Users")
{
queryable.OfType<Team>().Include(entity => entity.Users);
}
}
}
else
{
foreach (var propertyName in includeProperties)
{
queryable.Include(propertyName);
}
}
return queryable;
}
private static void ConfigureTeamTunerUser(EntityTypeBuilder<TeamTunerUser> builder)
{
ConfigureDescriptiveEntity(builder);
builder.HasMany(e => e.CardLevels)
.WithOne(e => e.User);
builder.HasOne(e => e.Team)
.WithMany(e => e.Users);
// Indexes and unique constraint
builder.HasIndex(e => e.Name)
.IsUnique();
builder.HasIndex(e => e.SppdName)
.IsUnique();
builder.HasIndex(e => e.Email)
.IsUnique();
}
我错过了什么？
Include / ThenInclude（和所有其他EF Core Queryable扩展）就像常规的LINQ Queryable方法（Select，Where，OrderBy等）修改源IQueryable<>并返回修改后的IQueryable<>。
在这里，您只是忘记使用生成的查询，所以
queryable.Include(propertyName);
具有相同的效果
queryable.Where(e => false);
即没有效果。
只需将代码更改为
queryable = queryable.Include(propertyName);
我注意到了一些问题。
您的方法仅适用于加载第一级导航属性。
foreach (var propertyName in includeProperties)
{
queryable.Include(propertyName);
}
您必须使用.ThenInclude()来加载嵌套导航属性。这打破了你作为构造函数的IEnumerable<string> includeProperties = null的方法。
第二个问题是您的测试本身。它只检查.Any()，但根据测试的名称，这是错误的断言。 （我们不知道测试是否失败，因为导航属性从未加载或者它已成功加载，但是没有Users。您应该只检查导航属性是否已加载。如下所示。
DbContext.Entry(createdTeamWithUsers).Navigation("Users").IsLoaded
您尝试将属性标记为虚拟属性吗？您需要它来根据文档启用延迟加载导航：
延迟加载
然后，EF Core将为任何可以覆盖的导航属性启用延迟加载 - 也就是说，它必须是虚拟的，并且可以继承自可以继承的类。例如，在以下实体中，Post.Blog和Blog.Posts导航属性将是延迟加载的。