Application.ApplicationExit Ereignis
Definition
Wichtig
Einige Informationen beziehen sich auf Vorabversionen, die vor dem Release ggf. grundlegend überarbeitet werden. Microsoft übernimmt hinsichtlich der hier bereitgestellten Informationen keine Gewährleistungen, seien sie ausdrücklich oder konkludent.
Tritt ein, wenn die Anwendung gerade beendet wird.
public:
static event EventHandler ^ ApplicationExit;public static event EventHandler ApplicationExit;public static event EventHandler? ApplicationExit;member this.ApplicationExit : EventHandler Public Shared Custom Event ApplicationExit As EventHandler Ereignistyp
Beispiele
Im folgenden Codebeispiel werden zwei Formulare angezeigt und die Anwendung beendet, wenn beide Formulare geschlossen werden. Wenn die Anwendung gestartet und beendet wird, wird die Position jedes Formulars gespeichert. In diesem Beispiel wird die Verwendung des ApplicationExit -Ereignisses veranschaulicht, um zu wissen, wann die Formularpositionen in der Datei beibehalten werden sollen und wann geschlossen FileStream werden soll.
Die -Klasse MyApplicationContext erbt von ApplicationContext und verfolgt, wann jedes Formular geschlossen wird, und beendet den aktuellen Thread, wenn beides ist. Die -Klasse speichert die Position jedes Formulars, wenn es geschlossen ist. Wenn das ApplicationExit Ereignis auftritt, schreibt die -Klasse die Positionen der einzelnen Für den Benutzer in die Datei. Die Formularpositionsdaten werden in einer Datei mit dem Titel appdata.txt gespeichert, die an dem durch UserAppDataPathfestgelegten Speicherort erstellt wird. Die Main -Methode ruft auf Application.Run(context) , um die Anwendung mit dem zu ApplicationContextstarten.
Dieser Code ist ein Auszug aus dem Beispiel in der ApplicationContext Klassenübersicht. Die gesamte Codeauflistung finden Sie ApplicationContext unter.
MyApplicationContext()
{
_formCount = 0;
// Handle the ApplicationExit event to know when the application is exiting.
Application::ApplicationExit += gcnew EventHandler( this, &MyApplicationContext::OnApplicationExit );
try
{
// Create a file that the application will store user specific data in.
_userData = gcnew FileStream( String::Concat( Application::UserAppDataPath, "\\appdata.txt" ),FileMode::OpenOrCreate );
}
catch ( IOException^ e )
{
// Inform the user that an error occurred.
MessageBox::Show( "An error occurred while attempting to show the application. The error is: {0}", dynamic_cast<String^>(e) );
// Exit the current thread instead of showing the windows.
ExitThread();
}
// Create both application forms and handle the Closed event
// to know when both forms are closed.
_form1 = gcnew AppForm1;
_form1->Closed += gcnew EventHandler( this, &MyApplicationContext::OnFormClosed );
_form1->Closing += gcnew CancelEventHandler( this, &MyApplicationContext::OnFormClosing );
_formCount++;
_form2 = gcnew AppForm2;
_form2->Closed += gcnew EventHandler( this, &MyApplicationContext::OnFormClosed );
_form2->Closing += gcnew CancelEventHandler( this, &MyApplicationContext::OnFormClosing );
_formCount++;
// Get the form positions based upon the user specific data.
if ( ReadFormDataFromFile() )
{
// If the data was read from the file, set the form
// positions manually.
_form1->StartPosition = FormStartPosition::Manual;
_form2->StartPosition = FormStartPosition::Manual;
_form1->Bounds = _form1Position;
_form2->Bounds = _form2Position;
}
// Show both forms.
_form1->Show();
_form2->Show();
}
void OnApplicationExit( Object^ /*sender*/, EventArgs^ /*e*/ )
{
// When the application is exiting, write the application data to the
// user file and close it.
WriteFormDataToFile();
try
{
// Ignore any errors that might occur while closing the file handle.
_userData->Close();
}
catch ( Exception^ )
{
}
}
private:
private MyApplicationContext()
{
_formCount = 0;
// Handle the ApplicationExit event to know when the application is exiting.
Application.ApplicationExit += new EventHandler(this.OnApplicationExit);
try
{
// Create a file that the application will store user specific data in.
_userData = new FileStream(Application.UserAppDataPath + "\\appdata.txt", FileMode.OpenOrCreate);
}
catch (IOException e)
{
// Inform the user that an error occurred.
MessageBox.Show("An error occurred while attempting to show the application." +
"The error is:" + e.ToString());
// Exit the current thread instead of showing the windows.
ExitThread();
}
// Create both application forms and handle the Closed event
// to know when both forms are closed.
_form1 = new AppForm1();
_form1.Closed += new EventHandler(OnFormClosed);
_form1.Closing += new CancelEventHandler(OnFormClosing);
_formCount++;
_form2 = new AppForm2();
_form2.Closed += new EventHandler(OnFormClosed);
_form2.Closing += new CancelEventHandler(OnFormClosing);
_formCount++;
// Get the form positions based upon the user specific data.
if (ReadFormDataFromFile())
{
// If the data was read from the file, set the form
// positions manually.
_form1.StartPosition = FormStartPosition.Manual;
_form2.StartPosition = FormStartPosition.Manual;
_form1.Bounds = _form1Position;
_form2.Bounds = _form2Position;
}
// Show both forms.
_form1.Show();
_form2.Show();
}
private void OnApplicationExit(object sender, EventArgs e)
{
// When the application is exiting, write the application data to the
// user file and close it.
WriteFormDataToFile();
try
{
// Ignore any errors that might occur while closing the file handle.
_userData.Close();
}
catch { }
}
Public Sub New()
MyBase.New()
_formCount = 0
' Handle the ApplicationExit event to know when the application is exiting.
AddHandler Application.ApplicationExit, AddressOf OnApplicationExit
Try
' Create a file that the application will store user specific data in.
_userData = New FileStream(Application.UserAppDataPath + "\appdata.txt", FileMode.OpenOrCreate)
Catch e As IOException
' Inform the user that an error occurred.
MessageBox.Show("An error occurred while attempting to show the application." +
"The error is:" + e.ToString())
' Exit the current thread instead of showing the windows.
ExitThread()
End Try
' Create both application forms and handle the Closed event
' to know when both forms are closed.
_form1 = New AppForm1()
AddHandler _form1.Closed, AddressOf OnFormClosed
AddHandler _form1.Closing, AddressOf OnFormClosing
_formCount = _formCount + 1
_form2 = New AppForm2()
AddHandler _form2.Closed, AddressOf OnFormClosed
AddHandler _form2.Closing, AddressOf OnFormClosing
_formCount = _formCount + 1
' Get the form positions based upon the user specific data.
If (ReadFormDataFromFile()) Then
' If the data was read from the file, set the form
' positions manually.
_form1.StartPosition = FormStartPosition.Manual
_form2.StartPosition = FormStartPosition.Manual
_form1.Bounds = _form1Position
_form2.Bounds = _form2Position
End If
' Show both forms.
_form1.Show()
_form2.Show()
End Sub
Private Sub OnApplicationExit(ByVal sender As Object, ByVal e As EventArgs)
' When the application is exiting, write the application data to the
' user file and close it.
WriteFormDataToFile()
Try
' Ignore any errors that might occur while closing the file handle.
_userData.Close()
Catch
End Try
End Sub
Hinweise
Sie müssen die Ereignishandler an das ApplicationExit Ereignis anfügen, um nicht behandelte, erforderliche Aufgaben auszuführen, bevor die Ausführung der Anwendung beendet wird. Sie können von dieser Anwendung geöffnete Dateien schließen oder Objekte verwerfen, die von der Garbage Collection nicht zurückgegeben wurden.
Da es sich um ein statisches Ereignis handelt, müssen Sie alle An dieses Ereignis angefügten Ereignishandler im ApplicationExit Ereignishandler selbst trennen. Wenn Sie diese Handler nicht trennen, bleiben sie an das Ereignis angefügt und verbrauchen weiterhin Arbeitsspeicher.
