AutomationEvent.EventRaised Event
[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]
Occurs when the Automation event occurs.
Assembly: System.Windows (in System.Windows.dll)
This event is useful for attaching managed event handlers to Automation events without requiring knowledge of the Automation event signatures. It also enables you to use Automation events with the standard Visual Basic event handling syntax. You can use this event with the AddHandler and RemoveHandler statements. You can also use the Handles keyword after storing the AutomationEvent reference in a variable by using the WithEvents keyword.
Alternately, you can attach managed event handlers directly to Automation events by using the += syntax in C#, and detach them using the -= syntax. You can also use the AddEventHandler method. However, in these cases, the specified delegate must have a signature that exactly matches the Automation event signature.
For more information about Automation, see Automation.
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Events with return values are not supported. Additionally, to use C# custom delegates with Automation events that have optional parameters, you must specify default parameter values in the delegate signature. In Visual Basic, delegate parameters cannot be optional, so you must handle the EventRaised event instead. |
The following code example demonstrates how to handle Automation events.
Private Sub SearchEmail() UpdateStatusMessage("Searching Inbox for 'WindowsPhone'...") ' The following code demonstrates three ways to handle Automation ' events. In Visual Basic, all three ways use the AutomationEvent class. searchEvent = AutomationFactory.GetEvent(outlook, "AdvancedSearchComplete") ' The first way is demonstrated by the Handles clause of the ' SearchEvent_EventRaised method, which requires the WithEvents modifier ' on the searchEvent variable declaration. ' The second way uses the AddHandler syntax with the EventRaised event, ' and does not require the WithEvents modifier. ' AddHandler searchEvent.EventRaised, AddressOf SearchEvent_EventRaised ' The third way uses the AutomationEvent.AddEventHandler method, and ' requires the use of a delegate with an API signature that matches the ' Automation event. ' searchEvent.AddEventHandler( ' New AdvancedSearchCompleteDelegate(AddressOf SearchComplete)) ' Begin the search. outlook.AdvancedSearch("Inbox", "urn:schemas:mailheader:subject ci_phrasematch 'WindowsPhone'", True, "SubjectSearch") End Sub Private WithEvents searchEvent As AutomationEvent Sub SearchEvent_EventRaised(ByVal sender As Object, ByVal e As AutomationEventArgs) Handles searchEvent.EventRaised SearchComplete(e.Arguments(0)) End Sub ' Required only with the second two ways of handling Automation events. ' Private Delegate Sub AdvancedSearchCompleteDelegate(ByRef search As Object) ' Note: Visual Basic does not support the use of custom delegates for ' events with optional parameters. Private Sub SearchComplete(ByRef search As Object) Dim searchResults As New List(Of String) For Each result As Object In search.Results searchResults.Add(result.Subject) Next SetResultsList(searchResults) End Sub
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