Timer.Enabled Proprietà

Definizione

Spazio dei nomi:

System.Windows.Forms

Assembly:

System.Windows.Forms.dll

Ottiene o imposta un valore che indica se il timer è in esecuzione.

public:
 virtual property bool Enabled { bool get(); void set(bool value); };

public virtual bool Enabled { get; set; }

member this.Enabled : bool with get, set

Public Overridable Property Enabled As Boolean

Valore della proprietà

Boolean

true se il timer è attualmente abilitato; in caso contrario, false. Il valore predefinito è false.

Esempio

Nell'esempio seguente viene implementato un semplice timer di intervallo, che imposta un allarme ogni cinque secondi. Quando si verifica l'allarme, viene MessageBox visualizzato un conteggio del numero di volte in cui l'allarme è stato avviato e richiede all'utente se il timer deve continuare a essere eseguito.

public ref class Class1
{
private:
   static System::Windows::Forms::Timer^ myTimer = gcnew System::Windows::Forms::Timer;
   static int alarmCounter = 1;
   static bool exitFlag = false;

   // This is the method to run when the timer is raised.
   static void TimerEventProcessor( Object^ /*myObject*/, EventArgs^ /*myEventArgs*/ )
   {
      myTimer->Stop();
      
      // Displays a message box asking whether to continue running the timer.
      if ( MessageBox::Show( "Continue running?", String::Format( "Count is: {0}", alarmCounter ), MessageBoxButtons::YesNo ) == DialogResult::Yes )
      {
         
         // Restarts the timer and increments the counter.
         alarmCounter += 1;
         myTimer->Enabled = true;
      }
      else
      {
         
         // Stops the timer.
         exitFlag = true;
      }
   }


public:
   static void Main()
   {
      
      /* Adds the event and the event handler for the method that will 
                process the timer event to the timer. */
      myTimer->Tick += gcnew EventHandler( TimerEventProcessor );
      
      // Sets the timer interval to 5 seconds.
      myTimer->Interval = 5000;
      myTimer->Start();
      
      // Runs the timer, and raises the event.
      while ( exitFlag == false )
      {
         
         // Processes all the events in the queue.
         Application::DoEvents();
      }
   }

};

int main()
{
   Class1::Main();
}

public class Class1 {
    static System.Windows.Forms.Timer myTimer = new System.Windows.Forms.Timer();
    static int alarmCounter = 1;
    static bool exitFlag = false;
 
    // This is the method to run when the timer is raised.
    private static void TimerEventProcessor(Object myObject,
                                            EventArgs myEventArgs) {
       myTimer.Stop();
 
       // Displays a message box asking whether to continue running the timer.
       if(MessageBox.Show("Continue running?", "Count is: " + alarmCounter, 
          MessageBoxButtons.YesNo) == DialogResult.Yes) {
          // Restarts the timer and increments the counter.
          alarmCounter +=1;
          myTimer.Enabled = true;
       }
       else {
          // Stops the timer.
          exitFlag = true;
       }
    }
 
    public static int Main() {
       /* Adds the event and the event handler for the method that will 
          process the timer event to the timer. */
       myTimer.Tick += new EventHandler(TimerEventProcessor);
 
       // Sets the timer interval to 5 seconds.
       myTimer.Interval = 5000;
       myTimer.Start();
 
       // Runs the timer, and raises the event.
       while(exitFlag == false) {
          // Processes all the events in the queue.
          Application.DoEvents();
       }
    return 0;
    }
 }

Public Class Class1
    Private Shared WithEvents myTimer As New System.Windows.Forms.Timer()
    Private Shared alarmCounter As Integer = 1
    Private Shared exitFlag As Boolean = False    
    
    ' This is the method to run when the timer is raised.
    Private Shared Sub TimerEventProcessor(myObject As Object, _
                                           ByVal myEventArgs As EventArgs) _
                                       Handles myTimer.Tick
        myTimer.Stop()
        
        ' Displays a message box asking whether to continue running the timer.
        If MessageBox.Show("Continue running?", "Count is: " & alarmCounter, _
                            MessageBoxButtons.YesNo) = DialogResult.Yes Then
            ' Restarts the timer and increments the counter.
            alarmCounter += 1
            myTimer.Enabled = True
        Else
            ' Stops the timer.
            exitFlag = True
        End If
    End Sub
    
    Public Shared Sub Main()
        ' Adds the event and the event handler for the method that will
        ' process the timer event to the timer.
        
        ' Sets the timer interval to 5 seconds.
        myTimer.Interval = 5000
        myTimer.Start()
        
        ' Runs the timer, and raises the event.
        While exitFlag = False
            ' Processes all the events in the queue.
            Application.DoEvents()
        End While

    End Sub    

End Class

Commenti

Il timer non è soggetto a Garbage Collection quando il valore è true.

La chiamata al metodo corrisponde all'impostazione StartEnabled su true. Analogamente, chiamare il metodo è lo stesso dell'impostazione StopEnabled su false.