C# 使用更新数据库命令MVC 4时出错

我创建了一个seed方法，但它无法填充我的“Ticket”表。其他两个表填充得很好

以下是Package Manager控制台中显示的错误：

Cannot insert the value NULL into column 'TicketID', table 'OnlineTicketSystemContext.dbo.Tickets';
column does not allow nulls.
INSERT fails.

以下是我对“票证”表的种子方法，它不会填充：

var tickets = new List<Ticket>
        {
            new Ticket{
                EmployeeID = employees.Single(s => s.Surname == "Alexander").EmployeeID,
                CustomerID = customers.Single(c => c.Surname == "Marsden").CustomerID,
                Summary = "Broken laptop screen",
                StartDate = DateTime.Parse("04/05/2012"),
                DueDate = DateTime.Parse("10/05/2012"),
                HardwareDelivered = true,
                Status = Status.Open,
                Priority = Priority.High
            },
            new Ticket{
                EmployeeID = employees.Single(s => s.Surname == "Marshall").EmployeeID,
                CustomerID = customers.Single(c => c.Surname == "Copper").CustomerID,
                Summary = "Keyboard doesnt work",
                StartDate = DateTime.Parse("09/07/2012"),
                DueDate = DateTime.Parse("12/07/2012"),
                HardwareDelivered = true,
                Status = Status.Open,
                Priority = Priority.High
            }
        };

        foreach (Ticket t in tickets)
        {
            var ticketInDataBase = context.Tickets.Where(
                s =>
                    s.Employee.EmployeeID == t.EmployeeID &&
                    s.Customer.CustomerID == t.CustomerID).SingleOrDefault();
            if (ticketInDataBase == null)
            {
                context.Tickets.Add(t);
            }
        }
        context.SaveChanges();

---

我按如下方式执行自动迁移：

  internal sealed class Configuration : DbMigrationsConfiguration<NetCollab.Web.Data.DataContext>
  {
    public Configuration()
    {
        AutomaticMigrationsEnabled = true;
        AutomaticMigrationDataLossAllowed = true;
        ContextKey = "NetCollab.Web.Data.DataContext";
    }

    protected override void Seed(NetCollab.Web.Data.DataContext context)
    {
        //  This method will be called after migrating to the latest version.


    }
}

---

AutomaticMigrationDataLossAllowed=true；我会解决那个问题的。或者，您可以删除该表并再次执行迁移

问题是，我的配置文件中已经有了这些精确的设置，看看前面的值。您可能需要手动清理某些内容。数据库中的TicketID是否设置为自动递增？或者你需要添加它吗？我想它应该默认自动递增？我的其他表是自动递增的，不需要任何数据注释。可能这列的数据库设置错误，我想看一下。

  internal sealed class Configuration : DbMigrationsConfiguration<NetCollab.Web.Data.DataContext>
  {
    public Configuration()
    {
        AutomaticMigrationsEnabled = true;
        AutomaticMigrationDataLossAllowed = true;
        ContextKey = "NetCollab.Web.Data.DataContext";
    }

    protected override void Seed(NetCollab.Web.Data.DataContext context)
    {
        //  This method will be called after migrating to the latest version.


    }
}