public JsonResult AddCase(CaseAddRequest request)
        {
            TableResponse response = new TableResponse();

            //开启事物
            using (var trans = _db.Database.BeginTransaction())
            {
                try
                {
                    //创建Case对象
                    var @case = new Case()
                    {
                        Cover         = request.Cover,
                        Name          = request.Name,
                        IndustryCases = new List <IndustryCase>(),
                        ColorCases    = new List <ColorCase>(),
                        ProductCases  = new List <ProductCase>(),
                        ClientCases   = new List <ClientCase>(),
                        CaseImages    = new List <CaseImage>()
                    };
                    //先存入Case对象
                    _db.Cases.Add(@case);
                    //保存后会有ID
                    _db.SaveChanges();
                    //存入行业关系
                    request.IndustryCases.ForEach(x =>
                    {
                        @case.IndustryCases.Add(new IndustryCase()
                        {
                            IndustryID = int.Parse(x)
                        });
                    });
                    //存入颜色关系
                    request.ColorCases.ForEach(x =>
                    {
                        @case.ColorCases.Add(new ColorCase()
                        {
                            ColorID = int.Parse(x)
                        });
                    });
                    //存入产品关系
                    request.ProductCases.ForEach(x =>
                    {
                        @case.ProductCases.Add(new ProductCase()
                        {
                            ProductID = int.Parse(x)
                        });
                    });
                    //存入客户端关系
                    request.ClientCases.ForEach(x =>
                    {
                        @case.ClientCases.Add(new ClientCase()
                        {
                            ClientID = int.Parse(x)
                        });
                    });
                    //存入详情图片
                    request.CaseImages.ForEach(x =>
                    {
                        @case.CaseImages.Add(new CaseImage()
                        {
                            Path = x
                        });
                    });
                    response.Total = _db.SaveChanges();
                    trans.Commit();
                }
                catch (Exception e)
                {
                    //若执行失败事物回滚
                    trans.Rollback();
                }
            }
            return(Json(response));
        }
        public JsonResult UpdateCase(CaseAddRequest request)
        {
            TableResponse response = new TableResponse();

            //开启事物
            using (var trans = _db.Database.BeginTransaction())
            {
                try
                {
                    //案例包含的所有关系
                    var @case = _db.Cases
                                .Include(x => x.CaseImages)
                                .Include(x => x.IndustryCases)
                                .Include(x => x.ColorCases)
                                .Include(x => x.ProductCases)
                                .Include(x => x.ClientCases)
                                .FirstOrDefault(x => x.ID == request.ID);
                    //清空多对多关系
                    @case.CaseImages.Clear();
                    @case.IndustryCases.Clear();
                    @case.ColorCases.Clear();
                    @case.ProductCases.Clear();
                    @case.ClientCases.Clear();
                    //修改值
                    @case.Cover = request.Cover;
                    @case.Name  = request.Name;
                    //存入行业关系
                    request.IndustryCases.ForEach(x =>
                    {
                        @case.IndustryCases.Add(new IndustryCase()
                        {
                            IndustryID = int.Parse(x)
                        });
                    });
                    //存入颜色关系
                    request.ColorCases.ForEach(x =>
                    {
                        @case.ColorCases.Add(new ColorCase()
                        {
                            ColorID = int.Parse(x)
                        });
                    });
                    //存入产品关系
                    request.ProductCases.ForEach(x =>
                    {
                        @case.ProductCases.Add(new ProductCase()
                        {
                            ProductID = int.Parse(x)
                        });
                    });
                    //存入客户端关系
                    request.ClientCases.ForEach(x =>
                    {
                        @case.ClientCases.Add(new ClientCase()
                        {
                            ClientID = int.Parse(x)
                        });
                    });
                    //存入详情图片
                    request.CaseImages.ForEach(x =>
                    {
                        @case.CaseImages.Add(new CaseImage()
                        {
                            Path = x
                        });
                    });
                    _db.Cases.Update(@case);
                    response.Total = _db.SaveChanges();
                    trans.Commit();
                }
                catch (Exception e)
                {
                    Debug.WriteLine(e.ToString());
                    //若执行失败事物回滚
                    trans.Rollback();
                }
            }
            return(Json(response));
        }