Entity Framework Adding Child Objects to DB

Question

I am currently stuck on adding a new child entity to my database using lamda queries. The structure of my database is that Area has a one to many relationship with Shifts

In my seeding database I populate the Shifts while creating the Areas:

new Area() 
{
    AreaDesc = "Area 1",
    AreaActive = true,
    AreaCreatedDate = DateTime.Now,
    SHFID = new Shift() 
    {
        StartTime = new TimeSpan (5,30,00),
        EndTime = new TimeSpan (11, 00, 00),
        RequiredResources = 2,
        ShiftDesc = "AM Shift",
        ShiftDayID = 1
    }
}

That works fine, where I am struggling and probably due to a simple lack of understanding on entity frameworks abilities is adding a new Shift to an existing Area .

So far I have the following

var AreaVal = _context.Areas.Where(a => a.AreaID == AreaID).ToList();

var Shift = new Shift
{ 
    Area = AreaVal,
    StartTime = StartTime,
    EndTime = EndTime,
    ShiftDayID = model.ShiftDayID,
    ShiftDesc = model.ShiftDesc
};

Thinking that once I had the correct Area (I have the ID coming from the model) I could load the Area and pass it as the Area parameter in the Shift and entity framework would know what to do.

The Error I get in the parser is:

Cannot implicitly convert type (Generic.List to Models.Area.

I have also considered going from the other direction using _context.Areas.Update() but have been unable to work that one out very well.

Extra Info, Model Structures

Shift.cs

public class Shift
{
    [Key]
    public int SHFID { get; set; }
    public TimeSpan StartTime { get; set; }
    public TimeSpan EndTime { get; set; }
    public int RequiredResources { get; set; }
    public string ShiftDesc { get; set; }
    public int ShiftDayID { get; set; }
    public DateTime ShiftExDateStart { get; set; }
    public DateTime ShiftExDateEnd { get; set; }
    public int ShiftExLevel { get; set; }
    public TimeSpan ShiftExStartTime { get; set; }
    public TimeSpan ShiftExEndTime { get; set; }
    public Area Area { get; set; }
}

Area.cs

public class Area
{
    [Key]
    public int AreaID { get; set; }
    public string AreaDesc { get; set; }
    public Boolean AreaActive { get; set; }
    public DateTime AreaCreatedDate { get; set; }
    public List<Shift> SHFID { get; set; }
    public Company Company { get; set;}
}

Answer 1

You are on the right track.

AreaVal needs to be a single entity ( Area ), not a list of entities ( List<Area> ). Then it should work as expected.

Change the line:

var AreaVal = _context.Areas.Where(a => a.AreaID == AreaID).ToList();

to

var AreaVal = _context.Areas.Where(a => a.AreaID == AreaID).Single();