MVC JsonResult 无法对 null 引用执行运行时绑定解决方法

MVC JsonResult 无法对 null 引用执行运行时绑定
代码一：

return Json(new datagrid

            {

                total = 3,

                rows = result.MerchantQualities.Select(s => new

                {

                    MerchantGroup = s.MerchantGroup.ToString(),

                    Installation = s.Installation,

                    Registeration = s.Registeration,

                    Deposit = s.Deposit,

                    Consumption = s.Consumption,

                    StartupApp = s.StartupApp,

                    ConsumptionAmount = s.ConsumptionAmount

                }),

                footer =

                {

                    MerchantGroup = "",

                    Installation = 0,

                    Registeration = 0,

                    Deposit = 0,

                    Consumption = 0,

                    StartupApp = 0,

                    ConsumptionAmount = 0

                }

            });

代码二：

return Json(new datagrid

            {

                total = 3,

                rows = result.MerchantQualities.Select(s => new

                {

                    MerchantGroup = s.MerchantGroup.ToString(),

                    Installation = s.Installation,

                    Registeration = s.Registeration,

                    Deposit = s.Deposit,

                    Consumption = s.Consumption,

                    StartupApp = s.StartupApp,

                    ConsumptionAmount = s.ConsumptionAmount

                })

            });

MVC里面，代码1 就是多了一个“footer”节点
然后就报错了：无法对 null 引用执行运行时绑定
为什么？
------解决方案--------------------
好的 我也已经解决了