C#：從 Net Core 中的 DbContext 繼承，構造函數：沒有為此 DbContext 配置數據庫提供程序

Question

我目前有 PropertyApplication DbContext 如下，

public partial class PropertyContext : DbContext
{
    public PropertyContext()
    {
    }

    public PropertyContext(DbContextOptions<PropertyContext> options)
        : base(options)
    {
    }

    public virtual DbSet<Address> Address { get; set; }
    public virtual DbSet<BoundaryChangeEvent> BoundaryChangeEvent { get; set; }

我想從這個 PropertyDbContext 中得到 inheritance。 這在構造函數中是否正確完成？ 試圖通過下面的單元測試，它會覆蓋保存更改以引入審核用戶信息。 只是好奇下面的構造函數語句是否正確？ 或者我應該嘗試使用 AuditablePropertyContext 選項嘗試下面的選項 2？

public class AuditablePropertyContext : PropertyContext
{
    private int _user;

    public AuditablePropertyContext()
    {
    }

    public AuditablePropertyContext(DbContextOptions<PropertyContext> options, UserResolverService userService)
        : base(options)
    {
        _user = userService.GetUser();
    }

    public void ApplyCreatedBy()
    {
        var modifiedEntities = ChangeTracker.Entries<ICreatedByUserId>().Where(e => e.State == EntityState.Added);
        foreach (var entity in modifiedEntities)
        {
            entity.Property("CreatedByUserId").CurrentValue = _user;
        }
    }

    public override int SaveChanges()
    {
        ApplyCreatedBy();
        return base.SaveChanges();
    }

}

選項 2：

我在嘗試執行此操作時收到錯誤，

public AuditablePropertyContext(DbContextOptions<AuditablePropertyContext> options, UserResolverService userService)
    : base(options)
{
    _user = userService.GetUser();
}

錯誤：

錯誤 CS1503 參數 1：無法從“Microsoft.EntityFrameworkCore.DbContextOptions IPTS.PropertyManagement.Infrastructure.Auditable.Data.AuditablePropertyContext”轉換為“Microsoft.EntityFrameworkCore.DbContextOptions IPTS.PropertyManagement.Infrastructure.Data.PropertyContext”

*有時公司使用 SQL 服務器，有時使用 InMemory，或 SQLite

單元測試失敗：

services.AddSingleton(a =>
{
    var mock = new Mock<IUserResolverService>();
    mock.Setup(b => b.GetUser()).Returns(5);
    return mock.Object;
});

services.AddDbContext<PropertyContext>(
    options => options.UseInMemoryDatabase("Ipts").UseQueryTrackingBehavior(QueryTrackingBehavior.TrackAll),
    ServiceLifetime.Singleton);
services.AddSingleton<DbContext, PropertyContext>();


services.AddDbContext<AuditablePropertyContext>(
    options => options.UseInMemoryDatabase("Ipts").UseQueryTrackingBehavior(QueryTrackingBehavior.TrackAll),
    ServiceLifetime.Singleton);
services.AddSingleton<AuditablePropertyContext>();

services.RegisterMappingProfiles(new ApplicationServicesMappingProfile(),
    new PropertyManagementDataMappingProfile());
return services;

}

單元測試：錯誤

Message: 
System.InvalidOperationException : No database provider has been configured for this DbContext. A provider can be configured by overriding the DbContext.OnConfiguring method or by using AddDbContext on the application service provider. If AddDbContext is used, then also ensure that your DbContext type accepts a DbContextOptions<TContext> object in its constructor and passes it to the base constructor for DbContext.
Stack Trace: 
DbContextServices.Initialize(IServiceProvider scopedProvider, IDbContextOptions contextOptions, DbContext context)
DbContext.get_InternalServiceProvider()
DbContext.get_DbContextDependencies()

Answer 1

將構造函數PropertyContext class 更改為以下代碼：

public PropertyContext(DbContextOptions options)
        : base(options)
    {
    }

然后將構造函數AuditablePropertyContext class 更改為以下代碼：

  public AuditablePropertyContext(DbContextOptions options, UserResolverService userService)
        : base(options)
    {
        _user = userService.GetUser();
    }

注意：不需要時刪除兩個類中的默認構造函數。

Answer 2

您還可以僅在具體子類型上提供專門的DbContextOptions<Repo> 。

例如

public abstract class BaseRepo: DbContext
{
    public BaseRepo(DbContextOptions options) : base(options)
    {

    }
}


public sealed class Repo : BaseRepo
{
    public Repo(DbContextOptions<Repo> options) : base(options)
    {

    }
}