using DevExpress.Xpo;
using DevExpress.Data.Filtering;

public class ProductLine : XPLiteObject {
    // ...
    public ProductLine(Session session) : base(session) { }

    // Gets a collection of products that correspond to the current product line.
    // XPO loads this collection on demand.
    [Association("ProductLine-Products")]
    public XPCollection<Product> Products { get { return GetCollection<Product>(nameof(Products)); } }

    string fName;
    public string Name {
       get { return fName; }
       set { SetPropertyValue(nameof(Name), ref fName, value); }
   }
}

public class Product: XPObject { 
    // ...

   ProductLine fLine;

   [Association("ProductLine-Products")]
   public ProductLine Line {
      get { return fLine; }
      set { SetPropertyValue(nameof(ProductLine), ref fLine, value); }
   }
 }

Imports DevExpress.Xpo
Imports DevExpress.Data.Filtering

Public Class ProductLine
    Inherits XPLiteObject

    ' ...
    Public Sub New(ByVal session As Session)
        MyBase.New(session)
    End Sub

    ' Gets a collection of products that correspond to the current product line.
    ' XPO loads this collection on demand.
    <Association("ProductLine-Products")>
    Public ReadOnly Property Products() As XPCollection(Of Product)
        Get
            Return GetCollection(Of Product)(nameof(Products))
        End Get
    End Property

    Private fName As String
    Public Property Name() As String
       Get
           Return fName
       End Get
       Set(ByVal value As String)
           SetPropertyValue(nameof(Name), fName, value)
       End Set
    End Property
End Class

Public Class Product
    Inherits XPObject

    ' ...

   Private fLine As ProductLine

   <Association("ProductLine-Products")>
   Public Property Line() As ProductLine
      Get
          Return fLine
      End Get
      Set(ByVal value As ProductLine)
          SetPropertyValue(nameof(ProductLine), fLine, value)
      End Set
   End Property
End Class

// Searches for the 'My Brand' product line.
// XPO does not populate the 'line.Products' collection.
ProductLine line = (ProductLine)session.FindObject(typeof(ProductLine), 
    CriteriaOperator.Parse("Name='My Brand'"));

// Reads the total number of objects in the collection.
// XPO populates the 'Products' collection. 
int count = line.Products.Count;

' Searches for the 'My Brand' product line.
' XPO does not populate the 'line.Products' collection.
Dim line As ProductLine = CType(session.FindObject(GetType(ProductLine), CriteriaOperator.Parse("Name='My Brand'")), ProductLine)

' Reads the total number of objects in the collection.
' XPO populates the 'Products' collection. 
Dim count As Integer = line.Products.Count

exec sp_executesql N'select N0."Oid",N1."Address",N2."Street",N2."City",N2."StateProvince",N2."ZipPostal",N2."Country",N2."OptimisticLockField",N2."GCRecord",N1."OptimisticLockField",N1."GCRecord",N1."ObjectType",N0."FirstName",N0."LastName",N0."MiddleName",N0."Birthday",N0."Email" from ((("dbo"."Person" N0
 inner join "dbo"."Party" N1 on (N0."Oid" = N1."Oid"))
 left join "dbo"."Address" N2 on (N1."Address" = N2."Oid"))
where N0."Oid" in (@p0,@p1)',N'@p0 uniqueidentifier,@p1 uniqueidentifier',@p0='85ECDEFA-1BE3-4AEF-A3CE-598F3C072599',@p1='F5EA5632-1BB0-408B-9E66-8441B4C216A8'

using DevExpress.Persistent.Base;
using DevExpress.Persistent.BaseImpl;
using DevExpress.Xpo;

[MapInheritance(MapInheritanceType.OwnTable)]
public abstract class Party : XPBaseObject {
    protected Party(Session session) : base(session) { }

    private Address fAddress;
    [Aggregated]
    public Address Address {
        get { return fAaddress; }
        set { SetPropertyValue(nameof(Address), ref fAddress, value); }
    }

    /* ... */
}

public class Person : Party { /* ... */ }

public class Address: XPBaseObject { /* ... */ }

Imports DevExpress.Persistent.Base
Imports DevExpress.Persistent.BaseImpl
Imports DevExpress.Xpo

<MapInheritance(MapInheritanceType.OwnTable)>
Public MustInherit Class Party
    Inherits XPBaseObject

    Protected Sub New(ByVal session As Session)
        MyBase.New(session)
    End Sub

    Private fAddress As Address
    <Aggregated>
    Public Property Address() As Address
        Get
            Return fAaddress
        End Get
        Set(ByVal value As Address)
            SetPropertyValue(nameof(Address), fAddress, value)
        End Set
    End Property

    ' ... 
End Class

Public Class Person
    Inherits Party

    ' ...
End Class

Public Class Address
    Inherits XPBaseObject

    ' ...
End Class

SELECT 
    (customer.FirstName + ' ' + customer.LastName) AS "Contact Name", 
    address.City, 
    (SELECT SUM(order.Amount) AS "Total Amount" FROM Orders order WHERE customer.ID = order.CustomerID) as "Total Amount"
FROM Customers customer
LEFT JOIN Addresses address ON customer.AddressID = address.ID

using DevExpress.Xpo;
// ...
XPView view = new XPView(unitOfWork, classInfo);
view.AddProperty("Contact Name", "Concat([FirstName], ' ', [LastName])");
view.AddProperty("City", "[Address.City]");
view.AddProperty("Total Amount", "[Orders].Sum([Amount])");

Imports DevExpres.Xpo
' ...
Dim view As New XPView(unitOfWork, classInfo)
view.AddProperty("Contact Name", "Concat([FirstName], ' ', [LastName])")
view.AddProperty("City", "[Address.City]")
view.AddProperty("Total Amount", "[Orders].Sum([Amount])")

using System.Linq;
// ...
var q1 = unitOfWork.Query<Customer>()
    .Select(c => new {
        ContactName = string.Concat(c.FirstName, " ", c.LastName),
        c.Address.City,
        TotalAmount = c.Orders.Sum(o => o.Amount)
    });

Imports System.Linq
' ...
Dim q1 = unitOfWork.Query(Of Customer)() _
    .Select(Function(c) New With { _
        Key .ContactName = String.Concat(c.FirstName, " ", c.LastName), _
        Key c.Address.City, _
        Key .TotalAmount = c.Orders.Sum(Function(o) o.Amount) _
    })

using System.Linq;
// ...
var q2 = unitOfWork.Query<Customer>()
    .Select(c => new CustomerDetails() {
        ContactName = string.Concat(c.FirstName, " ", c.LastName),
        City = c.Address.City,
        TotalAmount = c.Orders.Sum(o => o.Amount)
    });

Imports System.Linq
' ...
Dim q2 = unitOfWork.Query(Of Customer)(). _
    Select(Function(c) New CustomerDetails() With { _
        .ContactName = String.Concat(c.FirstName, " ", c.LastName), _
        .City = c.Address.City, _
        .TotalAmount = c.Orders.Sum(Function(o) o.Amount) _
    })

XPView view = new XPView(session, typeof(Boxer));  
view.AddProperty("Name");  
view.AddProperty("WinNumber");  
view.CriteriaString = "[<Boxer>][[^.Weight] >= floor(Weight / 10) * 10 and [^.Weight] <= floor(Weight / 10 + 1) * 10].max(WinNumber) = WinNumber";

Dim view As New XPView(session, GetType(Boxer))  
view.AddProperty("Name")  
view.AddProperty("WinNumber")  
view.CriteriaString = "[<Boxer>][[^.Weight] >= floor(Weight / 10) * 10 and [^.Weight] <= floor(Weight / 10 + 1) * 10].max(WinNumber) = WinNumber"

XPQuery<Boxer> boxers = new XPQuery<Boxer>(session);  
var list = from b in boxers  
            join bc in boxers  
            on bc.Weight >= Math.Floor(b.Weight / 10) * 10 &  
                bc.Weight <= Math.Floor(b.Weight / 10 + 1) * 10  
            into bcg  
            where b.WinNumber = bcg.Max(bcgi => bcgi.WinNumber)  
            select b;

Dim boxers As New XPQuery(Of Boxer)(session)  
Dim list = _  
      From b In boxers _  
      Join bc In boxers On bc.Weight >= Math.Floor(b.Weight / 10) * 10 AndAlso bc.Weight <= Math.Floor(b.Weight / 10 + 1) * 10 _  
      Into bcg = Group _  
      Where b.WinNumber = bcg.Max(Function(bcgi) bcgi.WinNumber) _  
      Select b