Timer.Interval Proprietà

Definizione

Spazio dei nomi:

System.Timers

Assembly:

System.ComponentModel.TypeConverter.dll

Source:

Timer.cs

Ottiene o imposta l'intervallo, espresso in millisecondi, in cui generare l'evento Elapsed.

public:
 property double Interval { double get(); void set(double value); };

public double Interval { get; set; }

member this.Interval : double with get, set

Public Property Interval As Double

Valore della proprietà

Double

Tempo tra gli eventi Elapsed, in millisecondi. Il valore deve essere maggiore di zero e minore o uguale a Int32.MaxValue. Il valore predefinito è 100 millisecondi.

Eccezioni

ArgumentException

L'intervallo è minore o uguale a zero.

-oppure-

L'intervallo è maggiore di Int32.MaxValue e il timer è attualmente abilitato. Non viene generata alcuna eccezione finché il timer non viene abilitato.

Esempio

Nell'esempio seguente viene creata un'istanza di un oggetto che genera Timer.Elapsed l'evento ogni due secondi (2000 millisecondi), configura un Timer gestore eventi per l'evento e avvia il timer. Il gestore eventi visualizza il valore della ElapsedEventArgs.SignalTime proprietà ogni volta che viene generato.

using namespace System;
using namespace System::Timers;

public ref class Example
{
private:
    static System::Timers::Timer^ aTimer;

public:
    static void Demo()
    {
        // Create a timer and set a two second interval.
        aTimer = gcnew System::Timers::Timer();
        aTimer->Interval = 2000;

        // Hook up the Elapsed event for the timer. 
        aTimer->Elapsed += gcnew System::Timers::ElapsedEventHandler(Example::OnTimedEvent);

        // Have the timer fire repeated events (true is the default)
        aTimer->AutoReset = true;

        // Start the timer
        aTimer->Enabled = true;

        Console::WriteLine("Press the Enter key to exit the program at any time... ");
        Console::ReadLine();
    }

private:
    static void OnTimedEvent(Object^ source, System::Timers::ElapsedEventArgs^ e)
    {
        Console::WriteLine("The Elapsed event was raised at {0}", e->SignalTime);
    }
};

int main()
{
    Example::Demo();
}
// The example displays output like the following: 
//       Press the Enter key to exit the program at any time... 
//       The Elapsed event was raised at 5/20/2015 8:48:58 PM 
//       The Elapsed event was raised at 5/20/2015 8:49:00 PM 
//       The Elapsed event was raised at 5/20/2015 8:49:02 PM 
//       The Elapsed event was raised at 5/20/2015 8:49:04 PM 
//       The Elapsed event was raised at 5/20/2015 8:49:06 PM

using System;
using System.Timers;

public class Example
{
    private static Timer aTimer;

    public static void Main()
    {
        // Create a timer and set a two second interval.
        aTimer = new System.Timers.Timer();
        aTimer.Interval = 2000;

        // Hook up the Elapsed event for the timer. 
        aTimer.Elapsed += OnTimedEvent;

        // Have the timer fire repeated events (true is the default)
        aTimer.AutoReset = true;

        // Start the timer
        aTimer.Enabled = true;

        Console.WriteLine("Press the Enter key to exit the program at any time... ");
        Console.ReadLine();
    }

    private static void OnTimedEvent(Object source, System.Timers.ElapsedEventArgs e)
    {
        Console.WriteLine("The Elapsed event was raised at {0}", e.SignalTime);
    }
}
// The example displays output like the following: 
//       Press the Enter key to exit the program at any time... 
//       The Elapsed event was raised at 5/20/2015 8:48:58 PM 
//       The Elapsed event was raised at 5/20/2015 8:49:00 PM 
//       The Elapsed event was raised at 5/20/2015 8:49:02 PM 
//       The Elapsed event was raised at 5/20/2015 8:49:04 PM 
//       The Elapsed event was raised at 5/20/2015 8:49:06 PM

open System.Timers

let onTimedEvent source (e: ElapsedEventArgs) =
    printfn $"The Elapsed event was raised at {e.SignalTime}"

// Create a timer and set a two second interval.
let aTimer = new Timer()
aTimer.Interval <- 2000

// Hook up the Elapsed event for the timer. 
aTimer.Elapsed.AddHandler onTimedEvent

// Have the timer fire repeated events (true is the default)
aTimer.AutoReset <- true

// Start the timer
aTimer.Enabled <- true

printfn "Press the Enter key to exit the program at any time... "
stdin.ReadLine() |> ignore

// The example displays output like the following: 
//       Press the Enter key to exit the program at any time... 
//       The Elapsed event was raised at 5/20/2015 8:48:58 PM 
//       The Elapsed event was raised at 5/20/2015 8:49:00 PM 
//       The Elapsed event was raised at 5/20/2015 8:49:02 PM 
//       The Elapsed event was raised at 5/20/2015 8:49:04 PM 
//       The Elapsed event was raised at 5/20/2015 8:49:06 PM

Imports System.Timers

Public Module Example
    Private aTimer As Timer

    Public Sub Main()
        ' Create a timer and set a two second interval.
        aTimer = New System.Timers.Timer()
        aTimer.Interval = 2000

        ' Hook up the Elapsed event for the timer.  
        AddHandler aTimer.Elapsed, AddressOf OnTimedEvent

        ' Have the timer fire repeated events (true is the default)
        aTimer.AutoReset = True

        ' Start the timer
        aTimer.Enabled = True

        Console.WriteLine("Press the Enter key to exit the program at any time... ")
        Console.ReadLine()
    End Sub

    Private Sub OnTimedEvent(source As Object, e As System.Timers.ElapsedEventArgs)
        Console.WriteLine("The Elapsed event was raised at {0}", e.SignalTime)
    End Sub
End Module
' The example displays output like the following: 
'       Press the Enter key to exit the program at any time... 
'       The Elapsed event was raised at 5/20/2015 8:48:58 PM 
'       The Elapsed event was raised at 5/20/2015 8:49:00 PM 
'       The Elapsed event was raised at 5/20/2015 8:49:02 PM 
'       The Elapsed event was raised at 5/20/2015 8:49:04 PM 
'       The Elapsed event was raised at 5/20/2015 8:49:06 PM

Commenti

Utilizzare la Interval proprietà per determinare la frequenza in cui viene attivato l'evento Elapsed . Poiché la Timer classe dipende dall'orologio di sistema, ha la stessa risoluzione dell'orologio di sistema. Ciò significa che l'evento Elapsed verrà generato a intervalli definiti dalla risoluzione dell'orologio di sistema se la Interval proprietà è minore della risoluzione dell'orologio di sistema. Nell'esempio seguente la Interval proprietà viene impostata su 5 millisecondi. Quando viene eseguito in un sistema Windows il cui orologio di sistema ha una risoluzione di circa 15 millisecondi, l'evento viene generato circa ogni 15 millisecondi anziché ogni 5 millisecondi.

Nota

L'orologio di sistema usato è lo stesso orologio usato da GetTickCount, che non è interessato dalle modifiche apportate con timeBeginPeriod e timeEndPeriod.

using System;
using System.IO;
using System.Collections.Generic;
using System.Timers;

public class Example
{
   private static Timer aTimer;
   private static List<String> eventlog;
   private static int nEventsFired = 0;
   private static DateTime previousTime;
       
   public static void Main()
   {
        eventlog = new List<String>();
        
        StreamWriter sr = new StreamWriter(@".\Interval.txt");
        // Create a timer with a five millisecond interval.
        aTimer = new Timer(5);
        aTimer.Elapsed += OnTimedEvent;
        // Hook up the Elapsed event for the timer. 
        aTimer.AutoReset = true;
        sr.WriteLine("The timer should fire every {0} milliseconds.", 
                     aTimer.Interval);
        aTimer.Enabled = true;

        Console.WriteLine("Press the Enter key to exit the program... ");
        Console.ReadLine();
        foreach (var item in eventlog)
           sr.WriteLine(item);
        sr.Close();
        Console.WriteLine("Terminating the application...");
   }

    private static void OnTimedEvent(Object source, ElapsedEventArgs e)
    {
        eventlog.Add(String.Format("Elapsed event at {0:HH':'mm':'ss.ffffff} ({1})", 
                                   e.SignalTime, 
                                   nEventsFired++ == 0 ? 
                                      0.0 : (e.SignalTime - previousTime).TotalMilliseconds));
        previousTime = e.SignalTime;
        if (nEventsFired == 20) {
           Console.WriteLine("No more events will fire...");
           aTimer.Enabled = false;
        }
    }
}
// The example writes output like the following to a file:
//       The timer should fire every 5 milliseconds.
//       Elapsed event at 08:42:49.370344 (0)
//       Elapsed event at 08:42:49.385345 (15.0015)
//       Elapsed event at 08:42:49.400347 (15.0015)
//       Elapsed event at 08:42:49.415348 (15.0015)
//       Elapsed event at 08:42:49.430350 (15.0015)
//       Elapsed event at 08:42:49.445351 (15.0015)
//       Elapsed event at 08:42:49.465353 (20.002)
//       Elapsed event at 08:42:49.480355 (15.0015)
//       Elapsed event at 08:42:49.495356 (15.0015)
//       Elapsed event at 08:42:49.510358 (15.0015)
//       Elapsed event at 08:42:49.525359 (15.0015)
//       Elapsed event at 08:42:49.540361 (15.0015)
//       Elapsed event at 08:42:49.555362 (15.0015)
//       Elapsed event at 08:42:49.570364 (15.0015)
//       Elapsed event at 08:42:49.585365 (15.0015)
//       Elapsed event at 08:42:49.605367 (20.002)
//       Elapsed event at 08:42:49.620369 (15.0015)
//       Elapsed event at 08:42:49.635370 (15.0015)
//       Elapsed event at 08:42:49.650372 (15.0015)
//       Elapsed event at 08:42:49.665373 (15.0015)

open System
open System.IO
open System.Timers

let aTimer = new Timer 5
let eventlog = ResizeArray()
let mutable nEventsFired = 0
let mutable previousTime = DateTime()
       
let onTimedEvent source (e: ElapsedEventArgs) =
    String.Format("Elapsed event at {0:HH':'mm':'ss.ffffff} ({1})", e.SignalTime, if nEventsFired = 0 then 0. else (e.SignalTime - previousTime).TotalMilliseconds)
    |> eventlog.Add
    nEventsFired <- nEventsFired + 1

    previousTime <- e.SignalTime

    if nEventsFired = 20 then
        printfn "No more events will fire..."
        aTimer.Enabled <- false

[<EntryPoint>]
let main _ =
    use sr = new StreamWriter(@".\Interval.txt")
    // Create a timer with a five millisecond interval.
    aTimer.Elapsed.AddHandler onTimedEvent
    // Hook up the Elapsed event for the timer. 
    aTimer.AutoReset <- true
    sr.WriteLine $"The timer should fire every {aTimer.Interval} milliseconds."
    aTimer.Enabled <- true

    printfn "Press the Enter key to exit the program... "
    stdin.ReadLine() |> ignore
    for item in eventlog do
        sr.WriteLine item
    printfn "Terminating the application..."
    0

// The example writes output like the following to a file:
//       The timer should fire every 5 milliseconds.
//       Elapsed event at 08:42:49.370344 (0)
//       Elapsed event at 08:42:49.385345 (15.0015)
//       Elapsed event at 08:42:49.400347 (15.0015)
//       Elapsed event at 08:42:49.415348 (15.0015)
//       Elapsed event at 08:42:49.430350 (15.0015)
//       Elapsed event at 08:42:49.445351 (15.0015)
//       Elapsed event at 08:42:49.465353 (20.002)
//       Elapsed event at 08:42:49.480355 (15.0015)
//       Elapsed event at 08:42:49.495356 (15.0015)
//       Elapsed event at 08:42:49.510358 (15.0015)
//       Elapsed event at 08:42:49.525359 (15.0015)
//       Elapsed event at 08:42:49.540361 (15.0015)
//       Elapsed event at 08:42:49.555362 (15.0015)
//       Elapsed event at 08:42:49.570364 (15.0015)
//       Elapsed event at 08:42:49.585365 (15.0015)
//       Elapsed event at 08:42:49.605367 (20.002)
//       Elapsed event at 08:42:49.620369 (15.0015)
//       Elapsed event at 08:42:49.635370 (15.0015)
//       Elapsed event at 08:42:49.650372 (15.0015)
//       Elapsed event at 08:42:49.665373 (15.0015)

Imports System.Collections.Generic
Imports System.IO
Imports System.Timers

Module Example
   Private WithEvents aTimer As Timer
   Private eventlog As List(Of String)
   Private nEventsFired As Integer = 0
   Private previousTime As Date

   Public Sub Main()
        eventlog = New List(Of String)()
        
        Dim sr As New StreamWriter(".\Interval.txt")
        ' Create a timer with a five millisecond interval.
        aTimer = New Timer(5)
        aTimer.AutoReset = True
        sr.WriteLine("The timer should fire every {0} milliseconds.", 
                     aTimer.Interval)
        aTimer.Enabled = True

        
        Console.WriteLine("Press the Enter key to exit the program... ")
        Console.ReadLine()
        For Each item In eventlog
           sr.WriteLine(item)
        Next
        sr.Close()
        Console.WriteLine("Terminating the application...")
   End Sub

    Private Sub OnTimedEvent(source As Object, e As ElapsedEventArgs) _
                             Handles aTimer.Elapsed
        eventlog.Add(String.Format("Elapsed event at {0:HH':'mm':'ss.ffffff} ({1})", 
                                   e.SignalTime, 
                                   If(nEventsFired = 0, 
                                      0.0, (e.SignalTime - previousTime).TotalMilliseconds)))
        nEventsFired += 1
        previousTime = e.SignalTime
        if nEventsFired = 20 Then
           Console.WriteLine("No more events will fire...")
           aTimer.Enabled = False
        End If
   End Sub
End Module
' The example displays the following output:
'       The timer should fire every 5 milliseconds.
'       Elapsed event at 08:42:49.370344 (0)
'       Elapsed event at 08:42:49.385345 (15.0015)
'       Elapsed event at 08:42:49.400347 (15.0015)
'       Elapsed event at 08:42:49.415348 (15.0015)
'       Elapsed event at 08:42:49.430350 (15.0015)
'       Elapsed event at 08:42:49.445351 (15.0015)
'       Elapsed event at 08:42:49.465353 (20.002)
'       Elapsed event at 08:42:49.480355 (15.0015)
'       Elapsed event at 08:42:49.495356 (15.0015)
'       Elapsed event at 08:42:49.510358 (15.0015)
'       Elapsed event at 08:42:49.525359 (15.0015)
'       Elapsed event at 08:42:49.540361 (15.0015)
'       Elapsed event at 08:42:49.555362 (15.0015)
'       Elapsed event at 08:42:49.570364 (15.0015)
'       Elapsed event at 08:42:49.585365 (15.0015)
'       Elapsed event at 08:42:49.605367 (20.002)
'       Elapsed event at 08:42:49.620369 (15.0015)
'       Elapsed event at 08:42:49.635370 (15.0015)
'       Elapsed event at 08:42:49.650372 (15.0015)
'       Elapsed event at 08:42:49.665373 (15.0015)

Se l'app richiede una risoluzione maggiore rispetto a quella offerta dalla Timer classe o dall'orologio di sistema, usare i timer multimediali a risoluzione elevata; vedere Procedura: Usare il timer High-Resolution.

Se l'intervallo viene impostato dopo l'avvio Timer , il conteggio viene reimpostato. Ad esempio, se si imposta l'intervallo su 5 secondi e quindi si imposta la Enabled proprietà su true, il conteggio inizia al momento Enabled . Se si reimposta l'intervallo su 10 secondi quando il conteggio è di 3 secondi, l'evento Elapsed viene generato per la prima volta 13 secondi dopo Enabled essere stato impostato su true.

Se Enabled è impostato su true e AutoReset viene impostato su false, Timer genera l'evento una sola volta, la prima volta che l'intervallo Elapsed viene trascorso. Enabled viene quindi impostato su false.

Nota

Se Enabled e sono entrambi impostati su falsee AutoReset il timer è stato abilitato in precedenza, l'impostazione Interval della proprietà causa la generazione dell'evento Elapsed una sola volta, come se la Enabled proprietà fosse stata impostata su true. Per impostare l'intervallo senza generare l'evento, è possibile impostare Enabled temporaneamente la proprietà su true, impostare la Interval proprietà sull'intervallo di tempo desiderato e quindi impostare immediatamente la Enabled proprietà su false.

Vedi anche

• AutoReset
• Enabled
• Elapsed