EventQuery Kelas

Definisi

Ruang nama:

System.Management

Rakitan:

System.Management.dll

Paket:

System.Management v8.0.0

Sumber:

ManagementQuery.cs

Mewakili kueri peristiwa WMI.

public ref class EventQuery : System::Management::ManagementQuery

public class EventQuery : System.Management.ManagementQuery

type EventQuery = class
    inherit ManagementQuery

Public Class EventQuery
Inherits ManagementQuery

Warisan

Object

ManagementQuery

EventQuery

Turunan

System.Management.WqlEventQuery

Contoh

Contoh berikut menunjukkan bagaimana klien menerima pemberitahuan saat instans Win32_Process dibuat karena kelas peristiwa __InstanceCreationEvent. Untuk informasi selengkapnya, lihat dokumentasi Instrumentasi Manajemen Windows . Klien menerima peristiwa secara sinkron dengan memanggil WaitForNextEvent metode . Contoh ini dapat diuji dengan memulai proses, seperti Notepad, saat kode contoh sedang berjalan.

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;
    }
}

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

Konstruktor

EventQuery()	Menginisialisasi instans baru kelas EventQuery. Ini adalah konstruktor tanpa parameter.
EventQuery(String)	Menginisialisasi instans EventQuery baru kelas untuk kueri yang ditentukan.
EventQuery(String, String)	Menginisialisasi instans EventQuery baru kelas untuk bahasa dan kueri yang ditentukan.

Properti

QueryLanguage	Mendapatkan atau mengatur bahasa kueri yang digunakan dalam string kueri, menentukan format string kueri. (Diperoleh dari ManagementQuery)
QueryString	Mendapatkan atau mengatur kueri dalam format teks. (Diperoleh dari ManagementQuery)

Metode

Clone()	Mengembalikan salinan objek.
Equals(Object)	Menentukan apakah objek yang ditentukan sama dengan objek saat ini. (Diperoleh dari Object)
GetHashCode()	Berfungsi sebagai fungsi hash default. (Diperoleh dari Object)
GetType()	Mendapatkan instans Type saat ini. (Diperoleh dari Object)
MemberwiseClone()	Membuat salinan dangkal dari yang saat ini Object. (Diperoleh dari Object)
ParseQuery(String)	Mengurai string kueri dan mengatur nilai properti yang sesuai. Jika kueri valid, properti nama kelas dan properti kondisi kueri akan diurai. (Diperoleh dari ManagementQuery)
ToString()	Mengembalikan string yang mewakili objek saat ini. (Diperoleh dari Object)