ManagementOperationObserver Class

Definition

Namespace:

System.Management

Assembly:

System.Management.dll

Package:

System.Management v9.0.0

Source:

ManagementOperationWatcher.cs

Manages asynchronous operations and handles management information and events received asynchronously.

public ref class ManagementOperationObserver

public class ManagementOperationObserver

type ManagementOperationObserver = class

Public Class ManagementOperationObserver

Inheritance

Object

ManagementOperationObserver

Examples

The following example demonstrates how to perform an asynchronous instance enumeration. The example uses the ManagementOperationObserver class to handle management information and events asynchronously.

using System;
using System.Management;

// This example demonstrates how
// to perform an asynchronous instance enumeration.

public class EnumerateInstancesAsync
{
    public EnumerateInstancesAsync()
    {
        // Enumerate asynchronously using Object Searcher
        // ===============================================

        // Instantiate an object searcher with the query
        ManagementObjectSearcher searcher =
            new ManagementObjectSearcher(new
            SelectQuery("Win32_Service"));

        // Create a results watcher object,
        // and handler for results and completion
        ManagementOperationObserver results = new
            ManagementOperationObserver();

        // Attach handler to events for results and completion
        results.ObjectReady += new
            ObjectReadyEventHandler(this.NewObject);
        results.Completed += new
            CompletedEventHandler(this.Done);

        // Call the asynchronous overload of Get()
        // to start the enumeration
        searcher.Get(results);

        // Do something else while results
        // arrive asynchronously
        while (!this.Completed)
        {
            System.Threading.Thread.Sleep (1000);
        }

        this.Reset();
    }

    private bool isCompleted = false;

    private void NewObject(object sender,
        ObjectReadyEventArgs obj)
    {
        Console.WriteLine("Service : {0}, State = {1}",
            obj.NewObject["Name"],
            obj.NewObject["State"]);
    }

    private bool Completed
    {
        get
        {
            return isCompleted;
        }
    }

    private void Reset()
    {
        isCompleted = false;
    }

    private void Done(object sender,
        CompletedEventArgs obj)
    {
        isCompleted = true;
    }

    public static void Main()
    {
        EnumerateInstancesAsync example =
            new EnumerateInstancesAsync();

        return;
    }
}

Imports System.Management

' This example demonstrates how
' to perform an asynchronous instance enumeration.

Public Class EnumerateInstancesAsync

    Public Sub New()

        Me.isCompleted = False

        ' Enumerate asynchronously using Object Searcher
        ' ===============================================

        ' Instantiate an object searcher with the query
        Dim searcher As ManagementObjectSearcher
        searcher = New ManagementObjectSearcher( _
            New SelectQuery("Win32_Service"))

        ' Create a results watcher object, 
        ' and handler for results and completion
        Dim results As ManagementOperationObserver
        results = New ManagementOperationObserver

        ' Attach handler to events for
        ' results and completion
        AddHandler results.ObjectReady, _
            AddressOf Me.NewObject
        AddHandler results.Completed, _
            AddressOf Me.Done

        ' Call the asynchronous overload of
        ' Get() to start the enumeration
        searcher.Get(results)

        ' Do something else while results 
        ' arrive(asynchronously)
        Do While (Me.Completed.Equals(False))

            System.Threading.Thread.Sleep(1000)
        Loop

        Me.Reset()

    End Sub

    Private isCompleted As Boolean

    Private Sub NewObject(ByVal sender As Object, _
        ByVal e As ObjectReadyEventArgs)

        Console.WriteLine("Service : {0}, State = {1}", _
         e.NewObject("Name"), e.NewObject("State"))
    End Sub

    Private ReadOnly Property Completed() As Boolean
        Get
            Return isCompleted
        End Get
    End Property

    Private Sub Reset()

        isCompleted = False
    End Sub

    Private Sub Done(ByVal sender As Object, _
        ByVal e As CompletedEventArgs)

        isCompleted = True
    End Sub


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

        Dim example As New EnumerateInstancesAsync

        Return 0

    End Function

End Class

Constructors

ManagementOperationObserver()

Initializes a new instance of the ManagementOperationObserver class. This is the parameterless constructor.

Methods

Cancel()	Cancels all outstanding operations.
Equals(Object)	Determines whether the specified object is equal to the current object. (Inherited from Object)
GetHashCode()	Serves as the default hash function. (Inherited from Object)
GetType()	Gets the Type of the current instance. (Inherited from Object)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
ToString()	Returns a string that represents the current object. (Inherited from Object)

Events

Completed	Occurs when an operation has completed.
ObjectPut	Occurs when an object has been successfully committed.
ObjectReady	Occurs when a new object is available.
Progress	Occurs to indicate the progress of an ongoing operation.