无法在EF Core标识列中插入显式值

Question

这是我的表结构。如您所见，我将操作号码定义为自动生成的值

这个表的映射： numOperation is defined autoGenerated increment and so on

modelBuilder.Entity<OperationComptable>(entity =>
            {
                entity.HasKey(e => e.NumOp)
                    .HasName("PK_OperationComptable");

                entity.Property(e => e.NumOp).ValueGeneratedOnAdd();

                entity.Property(e => e.DateOp).HasColumnType("date");

                entity.Property(e => e.LibelleOp)
                    .IsRequired()
                    .HasMaxLength(300);

                entity.Property(e => e.NatureOp).HasMaxLength(100);

                entity.Property(e => e.NumPieceJustificatifOp)
                    .IsRequired()
                    .HasMaxLength(50);

                entity.HasOne(d => d.IdExerciceComptableNavigation)
                    .WithMany(p => p.OperationComptable)
                    .HasForeignKey(d => d.IdExerciceComptable)
                    .OnDelete(DeleteBehavior.Restrict)
                    .HasConstraintName("FK_OperationComptable_OperationComptable");

                entity.HasOne(d => d.NumOpNavigation)
                    .WithOne(p => p.OperationComptable)
                    .HasForeignKey<OperationComptable>(d => d.NumOp)
                    .OnDelete(DeleteBehavior.Restrict)
                    .HasConstraintName("FK_OperationComptable_User");
            });

当我创建新实体时，我收到此错误“System.Data.SqlClient.SqlException：Impossible d'insérerunevaleur explicite dans lacolonneidentitédela table'OperationComptable'quand IDENTITY_INSERTestdéfiniàOFF” 这看起来很奇怪，因为当我创建新实例时，我没有设置身份。 此过程将由通用存储库执行，更具体地说，此方法：

public virtual TEntity Add(TEntity entity)
        {
            TEntity _entity = _unitOfWork.set<TEntity>().Add(entity).Entity;
            _entities.Entry(entity).State = EntityState.Added;
            return _entity;
        }

将由通用服务完全调用此代码示例：

public virtual TModel Create(TModel model)
        {           
            _logger.LogDebug("{method} called", nameof(Create));
            if (model == null)
            {
                throw new ArgumentNullException("entity " + typeof(TModel));
            }

            try
            {
                TEntity _entity = _builder.BuildModel(model);
                _entity = _repository.Add(_entity);
                _unitOfWork.Commit();
                return _builder.BuildEntity(_entity);
            }
            catch(Exception e)
            {
                return null;
            }           
        }