Linq Issue dealing with null values in select - linq

Question

I have the following entities in my solution
public class UtilityAccount : IObjectWithState
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public Guid UtilityAccountID { get; set; }
public string Account { get; set; }
[ForeignKey("Person")]
public Guid PersonID { get; set; }
public virtual Person Person { get; set; }
public string ForeignID { get; set; }
[NotMapped]
public ObjectState ObjectState { get; set; }
public virtual ICollection<Utility> Utilities { get; set; }
public UtilityAccount()
{
Utilities = new List<Utility>();
}
}
public class Utility : IObjectWithState
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public Guid UtilityID { get; set; }
[ForeignKey("UtilityAccount")]
public Guid UtilityAccountID { get; set; }
public virtual UtilityAccount UtilityAccount { get; set; }
public Guid? ServiceAddressID { get; set; }
[ForeignKey("ServiceAddressID")]
public virtual Address ServiceAddress { get; set; }
[NotMapped]
public ObjectState ObjectState { get; set; }
public double CurrentBalance { get; set; }
public double? PendingPaymentTotal { get; set; }
public string ForeignID { get; set; }
[ForeignKey("UtilityType")]
public Guid UtilityTypeID { get; set; }
public virtual UtilityType UtilityType { get; set; }
public virtual ICollection<UtilityBill> UtilityBills { get; set; }
public virtual ICollection<IncomingUtilityPayment> IncomingPayments { get; set; }
public Utility()
{
UtilityBills = new List<UtilityBill>();
IncomingPayments = new List<IncomingUtilityPayment>();
}
}
public class IncomingUtilityPayment : IObjectWithState
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public Guid IncomingPaymentID { get; set; }
public string ForeignID { get; set; }
[ForeignKey("Utility")]
public Guid UtilityID { get; set; }
public virtual Utility Utility { get; set; }
public DateTime PaymentDate { get; set; }
public IncomingPaymentStatus IncomingPaymentStatus { get; set; }
public double? UtilityAmount { get; set; }
public double? ConvenienceFee { get; set; }
public double? TotalAmount { get; set; }
public string AuthCode { get; set; }
public string AuthReference { get; set; }
public string TenderType { get; set; }
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int PaymentIdent { get; set; }
[NotMapped]
public ObjectState ObjectState { get; set; }
}
My problem is that I am trying to use Linq to retrieve information about a UtilityAccount and I am running into issues with the IncomingPayments for a Utility. Below is the select statement I am trying to use.
returnVal = repo.AllIncluding(o => o.Person, o => o.Utilities, o => o.Utilities.Select(p => p.UtilityType), o => o.Person.BillingAddress, o => o.Utilities.Select(p => p.ServiceAddress), o => o.Utilities.Select(p => p.IncomingPayments.Where(q => q.IncomingPaymentStatus == IncomingPaymentStatus.Pending || q.IncomingPaymentStatus == IncomingPaymentStatus.Processed )));
Everything ran fine until I added this clause to the statement.
o => o.Utilities.Select(p => p.IncomingPayments.Where(q => q.IncomingPaymentStatus == IncomingPaymentStatus.Pending || q.IncomingPaymentStatus == IncomingPaymentStatus.Processed ))
I think my issue ends up being something I am writing wrong in my Linq clause. The error I am getting is
The Include path expression must refer to a navigation property defined on the type. Use dotted paths for reference navigation properties and the Select operator for collection navigation properties.
Parameter name: path
I can use the following statement with no issues
o => o.Utilities.Select(p => p.IncomingPayments)
as soon as I add the where clause in I get the error

Answer 1

I'm not familiar with EntityFramework nor linq-to-entities, but if it's just like linq-to-object you can:
add a .Where(p => p.IncomingPayments != null) before chaining with your .Select() like this
o.Utilities.Where(p => p.IncomingPayments != null)
.Select(p => p.IncomingPayments.Where(q => q.IncomingPaymentStatus == IncomingPaymentStatus.Pending || q.IncomingPaymentStatus == IncomingPaymentStatus.Processed))
The result will be a nested IEnumerable, i.e. IEnumerable<IEnumerable<IncomingUtilityPayment>>
If you actually need a IEnumerable<IncomingUtilityPayment> then .SelectMany() come in to play.
o.Utilities.Where(p => p.IncomingPayments != null)
.SelectMany(p => p.IncomingPayments)
.Where(q => q.IncomingPaymentStatus == IncomingPaymentStatus.Pending || q.IncomingPaymentStatus == IncomingPaymentStatus.Processed)
Hope this help