Application.ApplicationExit Kejadian

Definisi

Ruang nama:

System.Windows.Forms

Rakitan:

System.Windows.Forms.dll

Sumber:

Application.cs

Terjadi ketika aplikasi akan dimatikan.

public:
 static event EventHandler ^ ApplicationExit;

public static event EventHandler? ApplicationExit;

member this.ApplicationExit : EventHandler 

Public Shared Custom Event ApplicationExit As EventHandler 

Jenis Acara

EventHandler

Contoh

Contoh kode berikut menampilkan dua formulir dan keluar dari aplikasi saat kedua formulir ditutup. Ketika aplikasi dimulai dan keluar, posisi setiap formulir diingat. Contoh ini menunjukkan penggunaan ApplicationExit peristiwa untuk mengetahui kapan posisi formulir harus dipertahankan ke file, dan kapan FileStream harus ditutup.

Kelas MyApplicationContext mewarisi dari dan melacak kapan setiap formulir ditutup, dan keluar dari ApplicationContext utas saat keduanya berada. Kelas mengingat posisi setiap formulir saat ditutup. ApplicationExit Ketika peristiwa terjadi, kelas menulis posisi masing-masing untuk pengguna ke file. Data posisi formulir disimpan dalam file berjudul appdata.txt yang dibuat di lokasi yang ditentukan oleh UserAppDataPath. Metode Main ini memanggil Application.Run(context) untuk memulai aplikasi yang ApplicationContextdiberikan .

Kode ini adalah kutipan dari contoh yang ditunjukkan dalam ApplicationContext gambaran umum kelas. Lihat ApplicationContext untuk seluruh daftar kode.

   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

Keterangan

Anda harus melampirkan penanganan aktivitas ke ApplicationExit peristiwa untuk melakukan tugas yang tidak tertangani dan diperlukan sebelum aplikasi berhenti berjalan. Anda dapat menutup file yang dibuka oleh aplikasi ini, atau membuang objek yang tidak diklaim kembali oleh pengumpulan sampah.

Karena ini adalah peristiwa statis, Anda harus melepaskan penanganan aktivitas apa pun yang terpasang pada peristiwa ini di penanganan aktivitas itu ApplicationExit sendiri. Jika Anda tidak melepaskan handler ini, handler ini akan tetap melekat pada peristiwa dan terus mengonsumsi memori.

Lihat juga

• Exit()