具有EF关系数据库映射的MVC

Question

I have this error when I try to update my database to population my tables.

PM> update-database

No pending explicit migrations.
Running Seed method.
System.InvalidOperationException: Sequence contains no matching element
   at System.Linq.Enumerable.Single[TSource](IEnumerable`1 source, Func`2 predicate)
   at RecreationServicesTicketingSystem.Migrations.Configuration.Seed(IssueContext context) in C:\Users\jwan\Documents\Visual Studio 2012\Projects\RecreationServicesTicketingSystem\RecreationServicesTicketingSystem\Migrations\Configuration.cs:line 60
   at System.Data.Entity.Migrations.DbMigrationsConfiguration`1.OnSeed(DbContext context)
   at System.Data.Entity.Migrations.DbMigrator.SeedDatabase()
   at System.Data.Entity.Migrations.Infrastructure.MigratorLoggingDecorator.SeedDatabase()
   at System.Data.Entity.Migrations.DbMigrator.Upgrade(IEnumerable`1 pendingMigrations, String targetMigrationId, String lastMigrationId)
   at System.Data.Entity.Migrations.Infrastructure.MigratorLoggingDecorator.Upgrade(IEnumerable`1 pendingMigrations, String targetMigrationId, String lastMigrationId)
   at System.Data.Entity.Migrations.DbMigrator.UpdateInternal(String targetMigration)
   at System.Data.Entity.Migrations.DbMigrator.<>c__DisplayClassc.<Update>b__b()
   at System.Data.Entity.Migrations.DbMigrator.EnsureDatabaseExists(Action mustSucceedToKeepDatabase)
   at System.Data.Entity.Migrations.Infrastructure.MigratorBase.EnsureDatabaseExists(Action mustSucceedToKeepDatabase)
   at System.Data.Entity.Migrations.DbMigrator.Update(String targetMigration)
   at System.Data.Entity.Migrations.Infrastructure.MigratorBase.Update(String targetMigration)
   at System.Data.Entity.Migrations.Design.ToolingFacade.UpdateRunner.Run()
   at System.AppDomain.DoCallBack(CrossAppDomainDelegate callBackDelegate)
   at System.AppDomain.DoCallBack(CrossAppDomainDelegate callBackDelegate)
   at System.Data.Entity.Migrations.Design.ToolingFacade.Run(BaseRunner runner)
   at System.Data.Entity.Migrations.Design.ToolingFacade.Update(String targetMigration, Boolean force)
   at System.Data.Entity.Migrations.UpdateDatabaseCommand.<>c__DisplayClass2.<.ctor>b__0()
   at System.Data.Entity.Migrations.MigrationsDomainCommand.Execute(Action command)
Sequence contains no matching element

I'm been googling around and no one seems to have a similar issue. It's on this Line var administrator = new List<Administrator> I put in a pointer as to where line 60 is.

Click Here Tables from SQL Server Management Studio

Click Here for Entity Models

 public Configuration()
        {
            AutomaticMigrationsEnabled = false;
        }
    protected override void Seed(RecreationalServicesTicketingSystem.DAL.IssueContext context)
    {

        var departments = new List<Department>
        {
            new Department { DepartmentID = 1, Name = "IT"},
            new Department { DepartmentID = 2, Name = "Admin" },
            new Department { DepartmentID = 3, Name = "Human Resources"},
            new Department { DepartmentID = 4, Name = "Mechanics" },
            new Department { DepartmentID = 5, Name = "Directors" },
            new Department { DepartmentID = 6, Name = "Operations"}

        };
        departments.ForEach(s => context.Departments.AddOrUpdate(p => p.Name, s));
        context.SaveChanges();


        var depots = new List<Depot>
        {
            new Depot { DepotID = 1, Name = "Porana"},
            new Depot { DepotID = 2, Name = "Far North"},


        };
        departments.ForEach(s => context.Departments.AddOrUpdate(p => p.Name, s));
        context.SaveChanges();

    var users = new List<User>
{
    new User { FirstMidName = "Jason",   LastName = "Wan",
        EnrollmentDate = DateTime.Parse("2016-02-18"), DepartmentID = 1, DepotID = 1},
    new User { FirstMidName = "Andy", LastName = "Domagas",
        EnrollmentDate = DateTime.Parse("2016-02-18"), DepartmentID = 1,DepotID = 1},
    new User { FirstMidName = "Denis",   LastName = "Djohar",
        EnrollmentDate = DateTime.Parse("2016-02-18"), DepartmentID = 1 ,DepotID = 1},
    new User { FirstMidName = "Christine",   LastName = "West",
        EnrollmentDate = DateTime.Parse("2016-02-18"), DepartmentID = 1, DepotID = 1},

};

        var administrator = new List<Administrator> <-- LINE 60
        {
            new Administrator {AdminID = 1, AdminRole = "Administrator LVL1", User = users.Single ( s => s.UserID == 1),
            Tickets = new List<Ticket>() },
            new Administrator {AdminID = 2, AdminRole = "Administrator LVL2", User = users.Single ( s => s.UserID == 2),
            Tickets = new List<Ticket>() },
            new Administrator {AdminID = 3, AdminRole = "Administrator LVL3", User = users.Single ( s => s.UserID == 3),
            Tickets = new List<Ticket>() }

        };
        administrator.ForEach(s => context.Administrators.AddOrUpdate(p => p.AdminID, s));
        context.SaveChanges();

        var categories = new List<Category>
        {
            new Category {CategoryID = 0001, Title = "Desktop"},
            new Category {CategoryID = 0002, Title = "Mobile"},
            new Category {CategoryID = 0003, Title = "Menzits"},
            new Category {CategoryID = 0004, Title = "XMPRO"},
            new Category {CategoryID = 0005, Title = "Con-X"},
            new Category {CategoryID = 0006, Title = "Promapp"},
            new Category {CategoryID = 0007, Title = "QGIS"},
        };
        categories.ForEach(s => context.Categories.AddOrUpdate(p => p.Title, s));
        context.SaveChanges();

        var tickets = new List<Ticket>
        {
            new Ticket {
                UserID = users.Single(s => s.LastName == "Wan").UserID,
                CategoryID = categories.Single(c => c.Title == "Con-X" ).CategoryID,
                Issue = ("Test Error 1"),
                Priority = Priority.High
            },
            new Ticket {
                UserID = users.Single(s => s.LastName == "Wan").UserID,
                CategoryID = categories.Single(c => c.Title == "Desktop" ).CategoryID,
                Issue = ("Test Error 2"),
                Priority = Priority.Med
            },
        };


        foreach (Ticket e in tickets)
        {
            var ticketInDataBase = context.Tickets.Where(
                s =>
                    s.User.UserID == e.UserID &&
                    s.Category.CategoryID == e.CategoryID).SingleOrDefault();
            if (ticketInDataBase == null)
            {
                context.Tickets.Add(e);
            }
        }
        context.SaveChanges();

    }
}

User.cs

public class User
    {

        public int UserID { get; set; }
        [StringLength(50, MinimumLength = 1)]
        public string LastName { get; set; }
        [StringLength(50, MinimumLength = 1, ErrorMessage = "First name cannot be longer than 50 characters.")]

        [Column("FirstName")]
        public string FirstMidName { get; set; }

        [DataType(DataType.Date)]
        [DisplayFormat(DataFormatString = "{0:yyyy-MM-dd}", ApplyFormatInEditMode = true)]
        public DateTime EnrollmentDate { get; set; }

        public string FullName
        {
            get { return LastName + ", " + FirstMidName; }
        }
        public int AdministratorID { get; set; }
        [ForeignKey("AdministratorID")]
        public virtual Administrator Administrator { get; set; }

        public int DepartmentID { get; set; }
        [ForeignKey("DepartmentID")]
        public virtual Department Department { get; set; }


        public int DepotID { get; set; }
        [ForeignKey("DepotID")]
        public virtual Depot Depot { get; set; }

        public int TicketID { get; set; }

        public virtual ICollection<Ticket> Users { get; set; }

    }

Department.cs

public class Department
{

    public int DepartmentID { get; set; }

    [StringLength(50, MinimumLength = 1)]
    public string Name { get; set; }

    public virtual ICollection<User> Users { get; set; }
}

Depot.cs

public class Depot
{

    public int DepotID { get; set; }
    [StringLength(50, MinimumLength = 1)]
    public string Name { get; set; }
    public virtual ICollection<User> Users { get; set; }

}

Answer 1

When you are creating your users you are not specifying the department they belong to, this means for an int field that by default it will be 0. There is no department in your database with id 0 therefore the foreign key constraint is violated. Try something like:

var users = new List<User>
        {
            new User { FirstMidName = "Jason",   LastName = "Wan",
                EnrollmentDate = DateTime.Parse("2016-02-18"), DepartmentId = 1 },
            new User { FirstMidName = "Andy", LastName = "Domagas",
                EnrollmentDate = DateTime.Parse("2016-02-18"), DepartmentId = 1 },
            new User { FirstMidName = "Denis",   LastName = "Djohar",
                EnrollmentDate = DateTime.Parse("2016-02-18"), DepartmentId = 1 },
            new User { FirstMidName = "Christine",   LastName = "West",
                EnrollmentDate = DateTime.Parse("2016-02-18"), DepartmentId = 1 },

        };

Update to solve the depot issue:

You are creating the depots, however the line that adds them to the context is referencing departments instead of depots:

 var depots = new List<Depot>
        {
            new Depot { DepotID = 1, Name = "Porana"},
            new Depot { DepotID = 2, Name = "Far North"},


        };
        departments.ForEach(s => context.Departments.AddOrUpdate(p => p.Name, s));// should be:
        depots.ForEach(s => context.Depots.AddOrUpdate(p => p.Name, s));
        context.SaveChanges();