EventWatcherOptions.BlockSize Propriété

Définition

Espace de noms:

System.Management

Assembly:

System.Management.dll

Paquet:

System.Management v8.0.0

Source:

ManagementOptions.cs

Obtient ou définit la taille de bloc pour les opérations de bloc. Pendant l'attente d'événements, cette valeur spécifie combien d'événements attendre avant de retourner une réponse.

public:
 property int BlockSize { int get(); void set(int value); };

public int BlockSize { get; set; }

member this.BlockSize : int with get, set

Public Property BlockSize As Integer

Valeur de propriété

Int32

Valeur entière indiquant la taille de bloc d’un bloc d’opérations.

Exemples

L’exemple suivant montre comment le client reçoit une notification lorsqu’un instance de Win32_Process est créé parce que la classe d’événements est __InstanceCreationEvent. Pour plus d’informations, consultez la documentation Windows Management Instrumentation . Le client reçoit les événements de façon synchrone en appelant la méthode WaitForNextEvent. Cet exemple peut être testé par le démarrage d'un processus, comme le Bloc-notes, alors que l'exemple de code est en cours d'exécution.

using System;
using System.Management;

// This example shows synchronous consumption of events.
// The client is blocked while waiting for events.

public class EventWatcherPolling
{
    public static int Main(string[] args)
    {
        // Create event query to be notified within 1 second of
        // a change in a service
        string query = "SELECT * FROM" +
            " __InstanceCreationEvent WITHIN 1 " +
            "WHERE TargetInstance isa \"Win32_Process\"";

        // Event options
        EventWatcherOptions eventOptions = new
            EventWatcherOptions();
        eventOptions.Timeout = System.TimeSpan.MaxValue;
        // return after 1 event is received
        eventOptions.BlockSize = 1;

        // Initialize an event watcher and subscribe to events
        // that match this query
        ManagementEventWatcher watcher =
            new ManagementEventWatcher("root\\CIMV2", query,
            eventOptions);

        // Block until the next event occurs
        // Note: this can be done in a loop if waiting for
        //        more than one occurrence
        Console.WriteLine(
            "Open an application (notepad.exe) to trigger an event.");
        ManagementBaseObject e = watcher.WaitForNextEvent();

        //Display information from the event
        Console.WriteLine(
            "Process {0} has been created, path is: {1}",
            ((ManagementBaseObject)e
            ["TargetInstance"])["Name"],
            ((ManagementBaseObject)e
            ["TargetInstance"])["ExecutablePath"]);

        //Cancel the subscription
        watcher.Stop();
        return 0;
    }
}

Imports System.Management

' This example shows synchronous consumption of events. 
' The client is blocked while waiting for events. 

Public Class EventWatcherPolling
    Public Overloads Shared Function _
        Main(ByVal args() As String) As Integer

        ' Create event query to be notified within 1 second of 
        ' a change in a service
        Dim query As String
        query = "SELECT * FROM" & _
            " __InstanceCreationEvent WITHIN 1 " & _
            "WHERE TargetInstance isa ""Win32_Process"""

        ' Event options
        Dim eventOptions As New EventWatcherOptions
        eventOptions.Timeout = System.TimeSpan.MaxValue
        ' return after 1 event is received
        eventOptions.BlockSize = 1


        ' Initialize an event watcher and subscribe to events 
        ' that match this query
        Dim watcher As New ManagementEventWatcher( _
            "root\CIMV2", query, eventOptions)

        ' Block until the next event occurs 
        ' Note: this can be done in a loop
        ' if waiting for more than one occurrence
        Console.WriteLine( _
          "Open an application (notepad.exe) to trigger an event.")
        Dim e As ManagementBaseObject = _
            watcher.WaitForNextEvent()

        'Display information from the event
        Console.WriteLine( _
            "Process {0} has created, path is: {1}", _
            CType(e("TargetInstance"), _
                ManagementBaseObject)("Name"), _
            CType(e("TargetInstance"), _
                ManagementBaseObject)("ExecutablePath"))

        'Cancel the subscription
        watcher.Stop()
        Return 0

    End Function 'Main
End Class

Remarques

Valeur de propriété

La valeur par défaut est 1.

Sécurité du .NET Framework

Confiance totale accordée à l'appelant immédiat. Ce membre ne peut pas être utilisé par du code d'un niveau de confiance partiel. Pour plus d’informations, consultez Utilisation de bibliothèques à partir de code partiellement approuvé.