Occurs when a property value changes.
Namespace:
System.ComponentModel
Assembly:
System (in System.dll)
'Usage
Dim instance As INotifyPropertyChanged
Dim handler As PropertyChangedEventHandler
AddHandler instance.PropertyChanged, handler
'Declaration
Event PropertyChanged As PropertyChangedEventHandler
The PropertyChanged event can indicate all properties on the object have changed by using either nullNothingnullptra null reference (Nothing in Visual Basic) or String..::.Empty as the property name in the PropertyChangedEventArgs.
The following code example demonstrates how to implement the PropertyChanged event of the INotifyPropertyChanged interface.
' This class implements a simple customer type
' that implements the IPropertyChange interface.
Public Class DemoCustomer
Implements INotifyPropertyChanged
' These fields hold the values for the public properties.
Private idValue As Guid = Guid.NewGuid()
Private customerNameValue As String = String.Empty
Private phoneNumberValue As String = String.Empty
Public Event PropertyChanged As PropertyChangedEventHandler _
Implements INotifyPropertyChanged.PropertyChanged
Private Sub NotifyPropertyChanged(ByVal info As String)
RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(info))
End Sub
' The constructor is private to enforce the factory pattern.
Private Sub New()
customerNameValue = "Customer"
phoneNumberValue = "(555)555-5555"
End Sub
' This is the public factory method.
Public Shared Function CreateNewCustomer() As DemoCustomer
Return New DemoCustomer()
End Function
' This property represents an ID, suitable
' for use as a primary key in a database.
Public ReadOnly Property ID() As Guid
Get
Return Me.idValue
End Get
End Property
Public Property CustomerName() As String
Get
Return Me.customerNameValue
End Get
Set(ByVal value As String)
If Not (value = customerNameValue) Then
Me.customerNameValue = value
NotifyPropertyChanged("CustomerName")
End If
End Set
End Property
Public Property PhoneNumber() As String
Get
Return Me.phoneNumberValue
End Get
Set(ByVal value As String)
If Not (value = phoneNumberValue) Then
Me.phoneNumberValue = value
NotifyPropertyChanged("PhoneNumber")
End If
End Set
End Property
End Class
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
.NET Framework
Supported in: 3.5, 3.0, 2.0
.NET Compact Framework
Supported in: 3.5, 2.0
XNA Framework
Supported in: 3.0, 2.0, 1.0
Reference