如何在 EntityFramework-Plus 的审计功能中使用代码优先？

Question

我正在尝试设置EntityFramework Plus' Audit Auto-Save feature，但看起来我遇到了一些非常愚蠢的问题。我正在遵循“通过覆盖 SaveChanges 和 SaveChangesAsync 自动保存”路径，但我正在尝试使用代码优先，因为我要使用它的项目已经像这样运行了一段时间了。话虽如此，我的 DbContext 看起来像这样：

public class CadastralDbContext : DbContext
{
    public CadastralDbContext(DbContextOptions<CadastralDbContext> options) : base(options) { }

    static CadastralDbContext()
    {
        AuditManager.DefaultConfiguration.AutoSavePreAction = (context, audit) =>
           (context as CadastralDbContext).AuditEntries.AddRange(audit.Entries);
    }

    public DbSet<AuditEntry> AuditEntries { get; set; }

    public DbSet<AuditEntryProperty> AuditEntryProperties { get; set; }

    //Ommited my DbSets

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.ApplyConfigurationsFromAssembly(typeof(CadastralDbContext).Assembly);
        /*** Ignore these for now ***/
        //modelBuilder.Entity<AuditEntry>().Ignore(x => x.Properties);
        //modelBuilder.Entity<AuditEntryProperty>().Ignore(x => x.Parent);
    }

    public override int SaveChanges()
    {
        var audit = new Audit();
        audit.PreSaveChanges(this);
        var rowAffecteds = base.SaveChanges();
        audit.PostSaveChanges();

        if (audit.Configuration.AutoSavePreAction != null)
        {
            audit.Configuration.AutoSavePreAction(this, audit);
            base.SaveChanges();
        }

        return rowAffecteds;
    }

    public async Task<int> SaveChangesAsync()
    {
        return await SaveChangesAsync(CancellationToken.None);
    }

    public override async Task<int> SaveChangesAsync(CancellationToken cancellationToken)
    {
        var audit = new Audit();
        audit.PreSaveChanges(this);
        var rowAffecteds = await base.SaveChangesAsync(cancellationToken).ConfigureAwait(false);
        audit.PostSaveChanges();

        if (audit.Configuration.AutoSavePreAction != null)
        {
            audit.Configuration.AutoSavePreAction(this, audit);
            await base.SaveChangesAsync(cancellationToken).ConfigureAwait(false);
        }

        return rowAffecteds;
    }
}

}

基本上，教程中添加了DbSet<AuditEntry> 和DbSet<AuditEntryProperty>，它们是框架本身的类。检查这些元数据，我们有：

//
// Summary:
//     An audit entry.
public class AuditEntry
{
    //
    // Summary:
    //     Gets or sets the object state entry.
    [NotMapped]
    public object Entity;
    //
    // Summary:
    //     Gets or sets the object state entry.
    [NotMapped]
    public EntityEntry Entry;
    //
    // Summary:
    //     Gets or sets the parent.
    public Audit Parent;

    public AuditEntry();

    //
    // Summary:
    //     Gets or sets the identifier of the audit entry.
    [Column(Order = 0)]
    public int AuditEntryID { get; set; }
    //
    // Summary:
    //     Gets or sets who created this object.
    [Column(Order = 5)]
    [MaxLength(255)]
    public string CreatedBy { get; set; }
    //
    // Summary:
    //     Gets or sets the the date of the changes.
    [Column(Order = 6)]
    public DateTime CreatedDate { get; set; }
    //
    // Summary:
    //     Gets or sets the name of the entity set.
    [Column(Order = 1)]
    [MaxLength(255)]
    public string EntitySetName { get; set; }
    //
    // Summary:
    //     Gets or sets the name of the entity type.
    [Column(Order = 2)]
    [MaxLength(255)]
    public string EntityTypeName { get; set; }
    //
    // Summary:
    //     Gets or sets the properties.
    public List<AuditEntryProperty> Properties { get; set; }
    //
    // Summary:
    //     Gets or sets the entry state.
    [Column(Order = 3)]
    public AuditEntryState State { get; set; }
    //
    // Summary:
    //     Gets or sets the name of the entry state.
    [Column(Order = 4)]
    [MaxLength(255)]
    public string StateName { get; set; }
}

和

//
// Summary:
//     An audit entry property.
public class AuditEntryProperty
{
    //
    // Summary:
    //     Gets or sets the new value audited.
    [NotMapped]
    public PropertyEntry PropertyEntry;
    public object NewValue;
    public object OldValue;

    public AuditEntryProperty();

    //
    // Summary:
    //     Gets or sets the name of the property internally.
    [NotMapped]
    public string InternalPropertyName { get; set; }
    //
    // Summary:
    //     Gets or sets a value indicating whether OldValue and NewValue is set.
    [NotMapped]
    public bool IsValueSet { get; set; }
    //
    // Summary:
    //     Gets or sets the name of the relation audited.
    [Column(Order = 2)]
    [MaxLength(255)]
    public string RelationName { get; set; }
    //
    // Summary:
    //     Gets or sets the name of the property audited.
    [Column(Order = 3)]
    [MaxLength(255)]
    public string PropertyName { get; set; }
    //
    // Summary:
    //     Gets or sets the parent.
    public AuditEntry Parent { get; set; }
    //
    // Summary:
    //     Gets or sets the identifier of the audit entry property.
    [Column(Order = 0)]
    public int AuditEntryPropertyID { get; set; }
    //
    // Summary:
    //     Gets or sets the new value audited formatted.
    [Column("NewValue", Order = 5)]
    public string NewValueFormatted { get; set; }
    //
    // Summary:
    //     Gets or sets the identifier of the audit entry.
    [Column(Order = 1)]
    public int AuditEntryID { get; set; }
    //
    // Summary:
    //     Gets or sets the old value audited formatted.
    [Column("OldValue", Order = 4)]
    public string OldValueFormatted { get; set; }
}

除了两个属性：public List<AuditEntryProperty> Properties { get; set; } 和 public AuditEntry Parent { get; set; } 之外，它看起来已经足够好了。由于它们未标记为 virtual，因此添加迁移将失败。我尝试了一种解决方法，只是想看看我是否可以让它生成表格，并且我确实成功了（之前评论过的那些行）：

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        //...
        modelBuilder.Entity<AuditEntry>().Ignore(x => x.Properties);
        modelBuilder.Entity<AuditEntryProperty>().Ignore(x => x.Parent);
    }

这似乎禁用了两个表都具有的 PrimaryKey-ForeignKey 关系，这些关系是在框架本身内部设置的，因为没有迹象表明我应该手动进行。我什至尝试运行脚本只是为了看看会发生什么，结果是灾难性的：

CREATE INDEX [IX_AuditEntryID] ON [dbo].[AuditEntryProperties]([AuditEntryID])

GO

ALTER TABLE [dbo].[AuditEntryProperties] 
ADD CONSTRAINT [FK_dbo.AuditEntryProperties_dbo.AuditEntries_AuditEntryID] 
FOREIGN KEY ([AuditEntryID])
REFERENCES [dbo].[AuditEntries] ([AuditEntryID])
ON DELETE CASCADE

GO

插入时出现以下 SQL 错误：String or binary data would be truncated。所以我只是回滚到之前的状态，框架有“50% 的输出”，因为每当用户请求插入、更新或删除操作时，它都会将记录保存到 AuditEntry 表（其中包含表等数据）但AuditEntryProperties（新值、旧值、列）中不会保留任何内容，除了那些被忽略的属性之外，我想不出其他任何东西是所有这些的原因。

我认为我可以同时覆盖 AuditEntry 和 AuditEntryProperties，但这听起来像是一个大而愚蠢的解决方法。我不是数据库专家，我在这里缺少什么？

编辑：忘记添加迁移代码：

        migrationBuilder.CreateTable(
            name: "AuditEntries",
            columns: table => new
            {
                AuditEntryID = table.Column<int>(nullable: false)
                    .Annotation("SqlServer:Identity", "1, 1"),
                CreatedBy = table.Column<string>(maxLength: 255, nullable: true),
                CreatedDate = table.Column<DateTime>(nullable: false),
                EntitySetName = table.Column<string>(maxLength: 255, nullable: true),
                EntityTypeName = table.Column<string>(maxLength: 255, nullable: true),
                State = table.Column<int>(nullable: false),
                StateName = table.Column<string>(maxLength: 255, nullable: true)
            },
            constraints: table =>
            {
                table.PrimaryKey("PK_AuditEntries", x => x.AuditEntryID);
            });

        migrationBuilder.CreateTable(
            name: "AuditEntryProperties",
            columns: table => new
            {
                AuditEntryPropertyID = table.Column<int>(nullable: false)
                    .Annotation("SqlServer:Identity", "1, 1"),
                AuditEntryID = table.Column<int>(nullable: false),
                PropertyName = table.Column<string>(maxLength: 255, nullable: true),
                RelationName = table.Column<string>(maxLength: 255, nullable: true),
                NewValue = table.Column<string>(nullable: true),
                OldValue = table.Column<string>(nullable: true)
            },
            constraints: table =>
            {
                table.PrimaryKey("PK_AuditEntryProperties", x => x.AuditEntryPropertyID);
            });

编辑 2 尝试使用 Fluent API 添加 FK：

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.ApplyConfigurationsFromAssembly(typeof(CadastralDbContext).Assembly);
        modelBuilder.Entity<AuditEntryProperty>().HasOne<AuditEntry>(prop => prop.Parent).WithMany(a => a.Properties).HasForeignKey(prop => prop.AuditEntryID);
    }

仍然无法执行迁移，因为这些属性不是虚拟的。

Answer 1

我们在EF Plus Issues Tracker 上创建了一个问题

您会在这里找到一个可以尝试的项目，我建议您继续在我们的问题跟踪器上进行讨论，因为 Stack Overflow 不是此类问题的平台。