Representa una
consulta de evento WMI.
Espacio de nombres: System.Management
Ensamblado: System.Management (en system.management.dll)
Visual Basic (Declaración)
Public Class EventQuery
Inherits ManagementQuery
Dim instance As EventQuery
public class EventQuery : ManagementQuery
public ref class EventQuery : public ManagementQuery
public class EventQuery extends ManagementQuery
public class EventQuery extends ManagementQuery
En el ejemplo siguiente se muestra cómo recibe una notificación el cliente cuando se crea una instancia de Win32_Process porque la clase de evento es __InstanceCreationEvent. Para obtener más información, consulte la documentación existente sobre Windows Management Instrumentation, en MSDN Library, http://msdn.microsoft.com/library/spa. El cliente recibe los eventos de forma sincrónica mediante una llamada al método WaitForNextEvent. Para probar este ejemplo, inicie un proceso, como Bloc de notas, mientras se ejecuta el código de ejemplo.
Imports System
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 New EventQuery
query.QueryString = "SELECT * FROM" & _
" __InstanceCreationEvent WITHIN 1 " & _
"WHERE TargetInstance isa ""Win32_Process"""
' Initialize an event watcher and subscribe to events
' that match this query
Dim watcher As New ManagementEventWatcher(query)
' times watcher.WaitForNextEvent in 5 seconds
watcher.Options.Timeout = New TimeSpan(0, 0, 50)
' 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 'EventWatcherPolling
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
EventQuery query = new EventQuery();
query.QueryString = "SELECT * FROM" +
" __InstanceCreationEvent WITHIN 1 " +
"WHERE TargetInstance isa \"Win32_Process\"";
// Initialize an event watcher and subscribe to events
// that match this query
ManagementEventWatcher watcher =
new ManagementEventWatcher(query);
// times out watcher.WaitForNextEvent in 5 seconds
watcher.Options.Timeout = new TimeSpan(0,0,5);
// 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;
}
}
System.Object
System.Management.ManagementQuery
System.Management.EventQuery
System.Management.WqlEventQuery
Seguridad para subprocesos
Los miembros estáticos públicos (Shared en Visual Basic) de este tipo son seguros para la ejecución de subprocesos. No se garantiza que los miembros de instancias sean seguros para la ejecución de subprocesos.
Windows 98, Windows 2000 SP4, Windows Millennium, Windows Server 2003, Windows XP Media Center, Windows XP Professional x64, Windows XP SP2, Windows XP Starter Edition
.NET Framework no admite todas las versiones de cada plataforma. Para obtener una lista de las versiones admitidas, vea Requisitos del sistema.
.NET Framework
Compatible con: 2.0, 1.1, 1.0