AutomationPropertyChangedEventArgs(AutomationProperty, Object, Object) 建構函式

定義

命名空間:

System.Windows.Automation

組件:

UIAutomationTypes.dll

初始化 AutomationPropertyChangedEventArgs 類別的新執行個體。

public:
 AutomationPropertyChangedEventArgs(System::Windows::Automation::AutomationProperty ^ property, System::Object ^ oldValue, System::Object ^ newValue);

public AutomationPropertyChangedEventArgs (System.Windows.Automation.AutomationProperty property, object oldValue, object newValue);

new System.Windows.Automation.AutomationPropertyChangedEventArgs : System.Windows.Automation.AutomationProperty * obj * obj -> System.Windows.Automation.AutomationPropertyChangedEventArgs

Public Sub New (property As AutomationProperty, oldValue As Object, newValue As Object)

參數

property

AutomationProperty

已變更之屬性的識別項。

oldValue

Object

屬性的舊值。

newValue

Object

屬性的新值。

範例

下列範例會在屬性變更時建構並引發 事件。

/// <summary>
/// Raises an event when the IsEnabled property on a control is changed.
/// </summary>
/// <param name="provider">The UI Automation provider for the control.</param>
/// <param name="newValue">The current enabled state.</param>
private void RaiseEnabledEvent(IRawElementProviderSimple provider, bool newValue)
{
    if (AutomationInteropProvider.ClientsAreListening)
    {
        AutomationPropertyChangedEventArgs args =
            new AutomationPropertyChangedEventArgs(AutomationElement.IsEnabledProperty,
                !newValue, newValue);
        AutomationInteropProvider.RaiseAutomationPropertyChangedEvent(provider, args);
    }
}

''' <summary>
''' Raises an event when the IsEnabled property on a control is changed.
''' </summary>
''' <param name="provider">The UI Automation provider for the control.</param>
''' <param name="newValue">The current enabled state.</param>
Private Sub RaiseEnabledEvent(ByVal provider As IRawElementProviderSimple, ByVal newValue As Boolean) 
    If AutomationInteropProvider.ClientsAreListening Then
        Dim args As New AutomationPropertyChangedEventArgs(AutomationElement.IsEnabledProperty, Not newValue, newValue)
        AutomationInteropProvider.RaiseAutomationPropertyChangedEvent(provider, args)
    End If

End Sub

備註

oldValue 如果先前的值尚未立即可用，可以在 null Visual Basic 中 (Nothing) 。