Question

当客户名称或代理商名称=空

时出错

 var results = db.Users.ToDataSourceResult(request, o => new
            {
                Id= o.Id,
                UserName = o.UserName,
                Email = o.Email,
                PhoneNumber = o.PhoneNumber,
                AgentName = o.Agent.FullName,
                CustomrName = o.Customer.Name 


            });

            return Json(results, JsonRequestBehavior.AllowGet);

Answer 1

如果您的意思是引用了引用错误，因为代理和客户未在用户类的构造函数中加载，则必须使用延迟加载

Public class user{
public user
(
agent=new Agent();
customer=new Customer();
)

}

Answer 2

您收到错误，因为您正在尝试访问Null对象的属性。在这种情况下，代理和客户属性。在尝试使用它们之前，您需要测试空值。

var results = db.Users.ToDataSourceResult(request, o => new
{
    Id = o.Id,
    UserName = o.UserName,
    Email = o.Email,
    PhoneNumber = o.PhoneNumber,
    AgentName = o.Agent == null ? null : o.Agent.FullName,
    CustomrName = o.Customer == null ? null : o.Customer.Name
});

return Json(results, JsonRequestBehavior.AllowGet);

或者，如果您使用的是C＃6，则可以使用新的简写

var results = db.Users.ToDataSourceResult(request, o => new
{
    Id = o.Id,
    UserName = o.UserName,
    Email = o.Email,
    PhoneNumber = o.PhoneNumber,
    AgentName = o.Agent?.FullName,
    CustomrName = o.Customer?.Name
});

return Json(results, JsonRequestBehavior.AllowGet);

Answer 3

我使用此代码并且工作了谢谢

var results = db.Users.Include("Customer").Include("Agent").ToDataSourceResult(request, o => new
            {
                Id = o.Id,
                UserName = o.UserName,
                Email = o.Email,
                PhoneNumber = o.PhoneNumber,
                AgentName = o.Agent?.FullName,
                CustomrName = o.Customer?.Name


            });

            return Json(results, JsonRequestBehavior.AllowGet);

当客户名称或代理商名称=空时，我收到错误

3 个答案: