C#-审核日志-如何从使用Fluent Api设计的模型中获取PK名称？

我试图在模型中获得主键名称，但我的数据库是用Fluent Api设计的，我找到的所有示例都是用DataAnnotation设计的

我正在重写DbContext的SaveChanges（）以创建审核日志

这是保存审核日志的代码

private List<AuditLogModel> GetAuditRecordsForChange(DbEntityEntry dbEntry, int? id_usuario = null)
    {
        List<AuditLogModel> result = new List<AuditLogModel>();

        DateTime changeTime = DateTime.Now;

        // Get the Table() attribute, if one exists
        TableAttribute tableAttr = dbEntry.Entity.GetType().GetCustomAttributes(typeof(TableAttribute), false).SingleOrDefault() as TableAttribute;

        // Get table name (if it has a Table attribute, use that, otherwise get the pluralized name)
        string tableName = tableAttr != null ? tableAttr.Name : dbEntry.Entity.GetType().Name;

        // Get primary key value (If you have more than one key column, this will need to be adjusted)
        //string keyName = dbEntry.Entity.GetType().GetProperties().Single(p => p.GetCustomAttributes(typeof(KeyAttribute), false).Count() > 0).Name;
        var oc = ((IObjectContextAdapter)this).ObjectContext;
        EntityKey key = oc.ObjectStateManager.GetObjectStateEntry(dbEntry.Entity).EntityKey;
        string keyName = key.EntitySetName;

        if (dbEntry.State == EntityState.Added)
        {
            // For Inserts, just add the whole record
            // If the entity implements IDescribableEntity, use the description from Describe(), otherwise use ToString()
            result.Add(new AuditLogModel()
            {
                Id_Usuario = id_usuario,
                Id_Registro = (int)dbEntry.CurrentValues.GetValue<object>(keyName),  // Again, adjust this if you have a multi-column key
                EventoTipo = "I", // INSERT
                Tabela = tableName,
                NovoValor = dbEntry.CurrentValues.ToObject().ToString()
            });
            //NovoValor = (dbEntry.CurrentValues.ToObject() is IDescribableEntity) ? (dbEntry.CurrentValues.ToObject() as IDescribableEntity).Describe() : dbEntry.CurrentValues.ToObject().ToString()
        }

        // Otherwise, don't do anything, we don't care about Unchanged or Detached entities

        return result;
    }

这是映射：

public AcessoLogMapping()
    {
        ToTable("TB_ACESSO_LOG");
        HasKey(x => x.Codigo);

        Property(x => x.Codigo).HasColumnName("ID_ACESSO_LOG")
            .HasColumnType("INT")
            .IsRequired();

        Property(x => x.CodigoUsuario).HasColumnName("ID_USUARIO_ACESSO_LOG")
            .HasColumnType("INT")
            .IsRequired();

        HasRequired(x => x.Usuario)
            .WithMany()
            .HasForeignKey(x => x.CodigoUsuario)
            .WillCascadeOnDelete(false);

        Property(x => x.Horario).HasColumnName("HORARIO_ACESSO_LOG")
            .HasColumnType("DATETIME")
            .IsRequired();

        Property(x => x.IP).HasColumnName("IP_ACESSO_LOG")
            .HasColumnType("VARCHAR")
            .HasMaxLength(180)
            .IsRequired();
    }

---

请注意，HasKey将Codigo确定为主键，并且模型中没有DataAnnotation。

这似乎适用于我：

 Id_Registro = entry.State == EntityState.Added ? null : ((IObjectContextAdapter)this).ObjectContext.ObjectStateManager.GetObjectStateEntry(entry.Entity).EntityKey.EntityKeyValues[0].Value.ToString()

---

这将引发NullReferenceException。EntityKeyValues为空。我在描述中添加了我的模型和映射，可能会有所帮助。

 Id_Registro = entry.State == EntityState.Added ? null : ((IObjectContextAdapter)this).ObjectContext.ObjectStateManager.GetObjectStateEntry(entry.Entity).EntityKey.EntityKeyValues[0].Value.ToString()