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Windows Forms Object Data Binding in .NET 2.0 -- Cont'd
By Rockford Lhotka |
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Conclusion
The new Windows Forms data binding features coming in .NET 2.0 and Visual Studio 2005 are very exciting. If you are a fan of the DataSet, the new smart DataTable objects will provide you with a way to encapsulate your business logic and data in a single object. If you prefer the object-oriented approach, as I do, then the new RAD support for objects will be very compelling. Personally I can't wait until I'm able to start building forms by simply using drag-and-drop to get my business objects onto a form!
About the Author
Rockford Lhotka is the author of numerous books, including the Expert One-on-One Visual Basic .NET & C# Business Objects books. He is a Microsoft Software Legend, Regional Director, MVP and INETA speaker. Rockford speaks at many conferences and user groups around the world and is a columnist for MSDN Online. Rockford is the Principal Technology Evangelist for Magenic Technologies, one of the nation's premiere Microsoft Gold Certified Partners dedicated to solving today's most challenging business problems using 100% Microsoft tools and technology.
Listing 1. Product class implementing IEditableObject
Imports System.ComponentModel
Public Class Product
Implements IPropertyChange
Implements IEditableObject
Public Event PropertyChanged(ByVal sender As Object, _
ByVal e As PropertyChangedEventArgs) _
Implements IPropertyChange.PropertyChanged
Private mName As String = ""
Private mPrice As Single
Private Sub New()
' require use of factory method
End Sub
Public Shared Function NewProduct( _
ByVal name As String, ByVal price As Single) As Product
Dim prod As New Product
prod.mNew = True
prod.Name = name
prod.Price = price
Return prod
End Function
Public Shared Function GetProduct( _
ByVal name As String, ByVal price As Single) As Product
Dim prod As New Product
prod.mNew = False
prod.Name = name
prod.Price = price
Return prod
End Function
Public Property Name() As String
Get
Return mName
End Get
Set(ByVal value As String)
mName = value
RaiseEvent PropertyChanged( _
Me, New PropertyChangedEventArgs("Name"))
End Set
End Property
Public Property Price() As Single
Get
Return mPrice
End Get
Set(ByVal value As Single)
mPrice = value
RaiseEvent PropertyChanged( _
Me, New PropertyChangedEventArgs("Price"))
End Set
End Property
#Region " IEditableObject "
Private mOldName As String
Private mOldPrice As Single
Private mEditing As Boolean
Private mParent As ProductList
Private mNew As Boolean
Friend Sub SetParent(ByVal parent As ProductList)
mParent = parent
End Sub
Public Sub BeginEdit() _
Implements System.ComponentModel.IEditableObject.BeginEdit
If Not mEditing Then
mOldName = mName
mOldPrice = mPrice
mEditing = True
End If
End Sub
Public Sub CancelEdit() _
Implements System.ComponentModel.IEditableObject.CancelEdit
If mNew Then
mParent.Remove(Me)
Else
mName = mOldName
mPrice = mOldPrice
End If
mEditing = False
End Sub
Public Sub EndEdit() _
Implements System.ComponentModel.IEditableObject.EndEdit
mEditing = False
mNew = False
End Sub
#End Region
End Class
Listing 2. ProductList class supporting IEditableObject in Product
Imports System.ComponentModel.Collections.Generic
Public Class ProductList
Inherits BindingList(Of Product)
Protected Overrides Function AddNewCore() As Object
Dim prod As Product = Product.NewProduct("", 0)
prod.SetParent(Me)
Add(prod)
Return prod
End Function
End Class
<< Data Binding a Form to an Object •
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Supporting Products/Tools
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Proposion N2N
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Proposion N2N connects Microsoft .NET applications to Lotus Notes and Lotus Domino databases. This ADO.NET managed data provider allows you to perform blindingly fast queries and updates of Notes data from ASP.NET pages, .NET web services, Windows, or Mobile applications. An innovative SQL-like query language leverages the unique features of Notes and makes collaborative software accessible to relational database programmers.
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