WqlEventQuery.WithinInterval Properti
Definisi
Penting
Beberapa informasi terkait produk prarilis yang dapat diubah secara signifikan sebelum dirilis. Microsoft tidak memberikan jaminan, tersirat maupun tersurat, sehubungan dengan informasi yang diberikan di sini.
Mendapatkan atau mengatur interval polling yang akan digunakan dalam kueri ini.
public:
property TimeSpan WithinInterval { TimeSpan get(); void set(TimeSpan value); };
public TimeSpan WithinInterval { get; set; }
member this.WithinInterval : TimeSpan with get, set
Public Property WithinInterval As TimeSpan
Nilai Properti
Mengembalikan nilai yang TimeSpan berisi interval polling yang digunakan dalam kueri peristiwa.
Contoh
Contoh berikut menginisialisasi baru WqlEventQuery yang mewakili kueri: "SELECT * FROM __InstanceCreationEvent WITHIN 1 WHERE TargetInstance ISA 'Win32_Process'".
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 new process being created
WqlEventQuery query =
new WqlEventQuery("__InstanceCreationEvent",
new TimeSpan(0,0,1),
"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 seconds of
' a process being created
Dim query As New WqlEventQuery( _
"__InstanceCreationEvent", _
New TimeSpan(0, 0, 1), _
"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, 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.")
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
Keterangan
Properti ini hanya boleh diatur dalam kasus di mana tidak ada penyedia peristiwa untuk peristiwa yang diminta, dan WMI diperlukan untuk melakukan polling untuk kondisi yang diminta.
Mengatur nilai properti ini akan menggantikan nilai sebelumnya yang disimpan dalam objek . String kueri dibangun kembali untuk mencerminkan interval baru.
Nilai Properti
Null, jika tidak ada polling yang terlibat; jika tidak, nilai yang valid TimeSpan jika polling diperlukan.
.NET Framework Security
Kepercayaan penuh untuk penelepon segera. Anggota ini tidak dapat digunakan oleh kode tepercaya sebagian. Untuk informasi selengkapnya, lihat Menggunakan Pustaka dari Kode Tepercaya Sebagian.