Question

How can I return return a collection in a method from a LINQ query that has a one to many relationship?

For instance, I have the following code where I can have many Projects to a TimeTracking object. Will the type that I have defined for the return type (IEnumerable) work? It is set up in my EF model as this specific kind of relationship.

public IEnumerable<TimeTracking> GetTimeTrackings()
        {
            YeagerTechEntities DbContext = new YeagerTechEntities();

            DbContext.Configuration.ProxyCreationEnabled = false;
            DbContext.Configuration.LazyLoadingEnabled = false;

            var timeTrackings = (from timeTrackingProjects in DbContext.TimeTrackings.Include("TimeTrackings.Projects")
                                 select timeTrackingProjects).Where(p => p.TimeTrackingID > 0);

            CloseConnection(DbContext);

            return timeTrackings;
        }

If so, when I display it in my MVC 3 View, and my View contains an IEnumerable<YeagerTech.YeagerTechWcfService.TimeTracking> model, will the model variable have records in it for the TimeTracking and Project objects? I don’t think it will. My TimeTracking object is set up as follows unless I need to inherit the Project class with it (which would then have the Project properties):

    public partial class TimeTracking
        {
            [DataMember]
            public int TimeTrackingID { get; set; }

            [DataMember]
            public short ProjectID { get; set; }

            [DataMember]
            public byte[] Attachment { get; set; }

            [Required]
            [DataType(DataType.Date)]
            [DataMember]
            public System.DateTime StartDate { get; set; }

            [Required]
            [DataType(DataType.Date)]
            [DataMember]
            public System.DateTime EndDate { get; set; }

            [DataMember]
            public string Notes { get; set; }

            [DataMember]
            public System.DateTime CreatedDate { get; set; }

            [DataMember]
            public Nullable<System.DateTime> UpdatedDate { get; set; }

            [DataMember]    
            public virtual Project Project { get; set; }
        }

I also want my View to display the Project text that is associated with the TimeTracking and not the Project value. How can I do this?Can someone please help?

I got the following msg from invoking a method on my WCF client.

‘cannot be serialized if reference tracking is disabled’

After getting the msg, I then modified my DataContracts to include references ([DataContract(IsReference = true)]).

namespace YeagerTechModel
{
    [Serializable]
    [DataContract(IsReference = true)]
    public partial class Customer
    {
        public Customer()
        {
            this.Projects = new HashSet<Project>();
        }

        [DataMember]
        public short CustomerID { get; set; }

        [Required]
        [StringLength(50)]
        [DataType(DataType.EmailAddress)]
        [DataMember]
        public string Email { get; set; }

I am executing the following server side code to successfully get data from my database in a parent/child relationship. The Include method explicity invokes getting the related Project data for the specific Customer. I had to do it this way because you must turn LazyLoading off if you want to get your parent/child data across the wire.

If I look at the WCF messagelog, I can see the actual data coming across in a Customer object and it has the Project object inside of the Customer object.

However, after the call is made and I actually inspect the contents of the “customer” variable, I don’t see any refernces to any Project data.

public IEnumerable<Customer> GetCustomers()
        {
            YeagerTechEntities DbContext = new YeagerTechEntities();

            DbContext.Configuration.ProxyCreationEnabled = false;
            DbContext.Configuration.LazyLoadingEnabled = false;

            IQueryable<Customer> customer = DbContext.Customers.Include("Projects").Where(p => p.CustomerID > 0);

            CloseConnection(DbContext);

            return customer;
        }

The thing I want to do now, is reference the Project data coming back from the call. However, I don’t get any Customer object intellisense after typing “customer.”. It’s all pertains to an IQueryable object.

I’m passing it back into my MVC Controller as the following type:

IEnumerable<YeagerTechWcfService.Customer> customerList = db.GetCustomers();

and into my View as the following model:

IEnumerable<YeagerTech.YeagerTechWcfService.Customer>

Now, the big question is “How can I reference the Project data coming back in my View?

The below is my code for the View, but there is no intellisense for “item.Project”. Note that “Email” is a property inside my Customer object.

foreach (var item in Model)
        {
        <tr>
            <td>
                @Html.DisplayFor(modelItem => item.Email)
            </td>

Answer 1

Actually, after further review, I can now see the Project collection in my Customer collection all the way back up to my client after adding a QucikWatch on the object.

The correct answer is the last part of my post where the LazyLoadingEnabled = false appears.