Primary key and relations with tables in ASP.NET MVC app - asp.net-mvc

Question

I have two tables called Seminari and Predbiljezbe.
When I create a new data row in table Predbiljezbe, I want the row to take the primary key of table Seminari and insert it into table Predbiljezbe.
I'm hoping I made it clear, be mindful that since I am new to programming and would like help very much thank. I apologize for my bad English.
Here is my code:
Controller:
public ActionResult Create()
{
return View();
}
[HttpPost]
public ActionResult Create(Predbiljezbe predbiljezbePrijava)
{
if (ModelState.IsValid)
{
context.Predbiljezbes.Add(predbiljezbePrijava);
context.SaveChanges();
return RedirectToAction("Index");
}
return View(predbiljezbePrijava);
}
Entity model:
public partial class SeminariEntities1 : DbContext
{
public SeminariEntities1()
: base("name=SeminariEntities1")
{
}
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
throw new UnintentionalCodeFirstException();
}
public virtual DbSet<Predbiljezbe> Predbiljezbes { get; set; }
public virtual DbSet<Seminari> Seminaris { get; set; }
}
Predbiljezbe model:
public partial class Predbiljezbe
{
public int IdPredbiljezba { get; set; }
public string Ime { get; set; }
public string Prezime { get; set; }
public string Datum { get; set; }
public string Adresa { get; set; }
public string Email { get; set; }
public string Telefon { get; set; }
public bool Status { get; set; }
public Nullable<int> IdSeminara { get; set; }
public Nullable<int> BrojPolaznika { get; set; }
public virtual Seminari Seminari { get; set; }
}
Seminari model:
public partial class Seminari
{
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2214:DoNotCallOverridableMethodsInConstructors")]
public Seminari()
{
this.Predbiljezbes = new HashSet<Predbiljezbe>();
}
public int IdSeminar { get; set; }
public string Naziv { get; set; }
public string Opis { get; set; }
public System.DateTime Datum { get; set; }
public Nullable<bool> Popunjen { get; set; }
public string Predavač { get; set; }
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly")]
public virtual ICollection<Predbiljezbe> Predbiljezbes { get; set; }
}

Answer 1

The way I do it is using double methods:
To insert into database and return Id
To insert dependent child using above Id
[HttpPost]
public ActionResult Create(Predbiljezbe predbiljezbePrijava)
{
if (ModelState.IsValid)
{
//add your first obj
context.Predbiljezbes.Add(predbiljezbePrijava);
context.SaveChanges();
//after saving in db its Id is automatically reflected in the object that you inserted
if(predbiljezbePrijava.Id != 0){
var seminariobj = new Seminari{ //insert your data }
// defining parentId into child
seminariobj.predbiljezbePrijavaId = predbiljezbePrijava.Id;
//save child obj
context.Seminari.Add(seminariobj);
context.SaveChanges();
}
return RedirectToAction("Index");
}
return View(predbiljezbePrijava);
}

Answer 2

I've tried your suggestion but i could not apply the solution to my problem,
Maybe there was an error in how I've set my tables and relations between them.
Here is my SQL query how i've set the tables in the database:
Seminari:
CREATE TABLE [dbo].[Seminari] (
[IdSeminar] INT IDENTITY (1, 1) NOT NULL,
[Naziv] NVARCHAR (MAX) NOT NULL,
[Opis] NVARCHAR (MAX) NULL,
[Datum] DATE NOT NULL,
[Popunjen] BIT NOT NULL,
[Predavač] NVARCHAR (50) NULL,
PRIMARY KEY CLUSTERED ([IdSeminar] ASC)
);
Predbilježbe:
CREATE TABLE [dbo].[Predbiljezbe] (
[IdPredbiljezba] INT IDENTITY (1, 1) NOT NULL,
[Ime] NVARCHAR (MAX) NOT NULL,
[Prezime] NVARCHAR (MAX) NOT NULL,
[Datum] NVARCHAR (MAX) NOT NULL,
[Adresa] NVARCHAR (MAX) NOT NULL,
[Email] NVARCHAR (MAX) NULL,
[Telefon] VARCHAR (MAX) NULL,
[Status] NVARCHAR (50) NULL,
[BrojPolaznika] INT NULL,
[IdSeminara] INT NULL,
CONSTRAINT [PK_Predbiljezbe] PRIMARY KEY CLUSTERED ([IdPredbiljezba] ASC),
CONSTRAINT [FK_Predbiljezbe_ToTable] FOREIGN KEY ([IdSeminara]) REFERENCES [dbo].[Seminari] ([IdSeminar])
);
Once again what i want is when i create new row in "Predbiljezbe" that column [IdSeminara] takes value of primary key [IdSeminar] from table "Seminari"!