INotifyPropertyChanged Interface
[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]
Notifies clients that a property value has changed.
Assembly: System (in System.dll)
The INotifyPropertyChanged type exposes the following members.
The INotifyPropertyChanged interface is used to notify clients, typically binding clients, that a property value has changed.
For example, consider a Person object with a property called FirstName. To provide generic property-change notification, the Person type implements the INotifyPropertyChanged interface and raises a PropertyChanged event when FirstName is changed.
The following code example demonstrates the how to implement the INotifyPropertyChanged interface.
'Add Imports statements Imports System.ComponentModel Imports System.Windows.Data ... ' Create a class that implements INotifyPropertyChanged Public Class Person Implements INotifyPropertyChanged Private firstNameValue As String Public Property FirstName() As String Get Return firstNameValue End Get Set(ByVal value As String) ' Only update if the value has changed If (value <> firstNameValue) Then firstNameValue = value ' Call NotifyPropertyChanged when the property is updated NotifyPropertyChanged("FirstName") End If End Set End Property ' Declare the PropertyChanged event Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged ' NotifyPropertyChanged will raise the PropertyChanged event passing the ' source property that is being updated. Public Sub NotifyPropertyChanged(ByVal propertyName As String) RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(propertyName)) End Sub End Class
