Exploring Cool Features of Devexpress' ASPxGridView

By Paul Kimmel

Listing 1: The code generated from the XPO Persistent Classes item installed when you install Devexpress controls.

Imports System
Imports DevExpress.Xpo
Namespace northwind

   Public Class Products
      Inherits XPLiteObject
      Dim fProductID As Integer
      <Key(true)> _
      Public Property ProductID() As Integer
         Get
            Return fProductID
         End Get
         Set(ByVal value As Integer)
            SetPropertyValue(Of Integer)("ProductID", _
                                         fProductID, value)
         End Set
      End Property

      Dim fProductName As String
      <Size(40)> _
      Public Property ProductName() As String
         Get
            Return fProductName
         End Get
         Set(ByVal value As String)
            SetPropertyValue(Of String)("ProductName",
                                        fProductName, value)
         End Set
      End Property
      Dim fSupplierID As Integer
      Public Property SupplierID() As Integer
         Get
            Return fSupplierID
         End Get
         Set(ByVal value As Integer)
            SetPropertyValue(Of Integer)("SupplierID",
                                         fSupplierID, value)
         End Set
      End Property
      Dim fCategoryID As Integer
      Public Property CategoryID() As Integer
         Get
            Return fCategoryID
         End Get
         Set(ByVal value As Integer)
            SetPropertyValue(Of Integer)("CategoryID",
                                         fCategoryID, value)
         End Set
      End Property
      Dim fQuantityPerUnit As String
      <Size(20)> _
      Public Property QuantityPerUnit() As String
         Get
            Return fQuantityPerUnit
         End Get
         Set(ByVal value As String)
            SetPropertyValue(Of String)("QuantityPerUnit",
                                        fQuantityPerUnit, value)
         End Set
      End Property
      Dim fUnitPrice As Decimal
      Public Property UnitPrice() As Decimal
         Get
            Return fUnitPrice
         End Get
         Set(ByVal value As Decimal)
            SetPropertyValue(Of Decimal)("UnitPrice",
                                         fUnitPrice, value)
         End Set
      End Property
      Dim fUnitsInStock As Short
      Public Property UnitsInStock() As Short
         Get
            Return fUnitsInStock
         End Get
         Set(ByVal value As Short)
            SetPropertyValue(Of Short)("UnitsInStock",
                                       fUnitsInStock, value)
         End Set
      End Property
      Dim fUnitsOnOrder As Short
      Public Property UnitsOnOrder() As Short
         Get
            Return fUnitsOnOrder
         End Get
         Set(ByVal value As Short)
            SetPropertyValue(Of Short)("UnitsOnOrder",
                                       fUnitsOnOrder, value)
         End Set
      End Property
      Dim fReorderLevel As Short
      Public Property ReorderLevel() As Short
         Get
            Return fReorderLevel
         End Get
         Set(ByVal value As Short)
            SetPropertyValue(Of Short)("ReorderLevel",
                                       fReorderLevel, value)
         End Set
      End Property
      Dim fDiscontinued As Boolean
      Public Property Discontinued() As Boolean
         Get
            Return fDiscontinued
         End Get
         Set(ByVal value As Boolean)
            SetPropertyValue(Of Boolean)("Discontinued",
                                         fDiscontinued, value)
         End Set
      End Property
      Public Sub New(ByVal session As Session)
         MyBase.New(session)
      End Sub
      Public Sub New()
         MyBase.New(Session.DefaultSession)
      End Sub
      Public Overrides Sub AfterConstruction()
         MyBase.AfterConstruction()
      End Sub
   End Class
End Namespace

The generated code is straightforward. The class represents the table, and the properties represent the table columns. The setters have a call to a generic SetPropertyValue method that, if I had to guess, I would say it contains a unified dirty-state tracking mechanism. A quick scan of Reflector says it looks like SetPropertyValue checks to see whether the new value is identical to the old value and raises some events and updates the Session's version of the property state.

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