Export (0) Print
Expand All

MessageQueueCriteria Class

Filters message queues when performing a query using the MessageQueue class's GetPublicQueues method.

Namespace: System.Messaging
Assembly: System.Messaging (in system.messaging.dll)

public class MessageQueueCriteria
public class MessageQueueCriteria
public class MessageQueueCriteria
Not applicable.

The MessageQueue class provides a number of methods that enable you to filter your search for public queues on the network. Specific methods for filtering by queue label, category, or server location are the GetPublicQueuesByLabel, GetPublicQueuesByCategory, and GetPublicQueuesByMachine.

The MessageQueueCriteria class, when used with the GetPublicQueues method, allows you to refine your filter. You can specify search criteria not specifically addressed through one of the GetPublicQueuesBy* methods, or by multiple criteria. You can pass a MessageQueueCriteria instance into the GetPublicQueues method in order to search, for example, by queue creation or modification times, the computer the queue resides on, the queue label or category, or any combination of these properties.

When filtering by multiple properties, the criteria are composed by applying the AND operator to the set of properties. Thus, when you specify a value for the CreatedAfter property together with the MachineName property, you are asking for all queues that were created after a specified time and that reside on a specific computer.

When you set any property, the method that sets the property also sets a flag to indicate that it should be included in the filter you are building. You cannot remove individual properties from the search filter. Instead, you remove all properties from the filter by calling ClearAll, and then set the properties that you do want to build into the search filter. ClearAll resets all properties into a "not set" default state.

You must set a property before trying to read it; otherwise, an exception is thrown.

The following example iterates through message queues and displays the path of each queue that was created in the last day and that exists on the computer "MyComputer".

using System;
using System.Messaging;

namespace MyProject
{
	/// <summary>
	/// Provides a container class for the example.
	/// </summary>
	public class MyNewQueue
	{

		//**************************************************
		// Provides an entry point into the application.
		//		 
		// This example uses a cursor to step through the
		// message queues and list the public queues on the
		// network that specify certain criteria.
		//**************************************************

		public static void Main()
		{
			// Create a new instance of the class.
			MyNewQueue myNewQueue = new MyNewQueue();

			// Output the count of Lowest priority messages.
			myNewQueue.ListPublicQueuesByCriteria();
						
			return;
		}


		//**************************************************
		// Iterates through message queues and displays the
		// path of each queue that was created in the last
		// day and that exists on the computer "MyComputer". 
		//**************************************************
		
		public void ListPublicQueuesByCriteria()
		{
			uint numberQueues = 0;
			
			// Specify the criteria to filter by.
			MessageQueueCriteria myCriteria = new 
				MessageQueueCriteria();
			myCriteria.MachineName = "MyComputer";
			myCriteria.CreatedAfter = DateTime.Now.Subtract(new 
				TimeSpan(1,0,0,0));
	

			// Get a cursor into the queues on the network.
			MessageQueueEnumerator myQueueEnumerator = 
				MessageQueue.GetMessageQueueEnumerator(myCriteria);

			// Move to the next queue and read its path.
			while(myQueueEnumerator.MoveNext())
			{
				// Increase the count if priority is Lowest.
				Console.WriteLine(myQueueEnumerator.Current.Path);
				numberQueues++;
			}

			// Handle no queues matching the criteria.
			if (numberQueues == 0)
			{
				Console.WriteLine("No public queues match criteria.");
			}

			return;
		}
	}
}

package MyProject;

import System.*;
import System.Messaging.*;

/// <summary>
/// Provides a container class for the example.
/// </summary>
public class MyNewQueue
{
    //**************************************************
    // Provides an entry point into the application.
    //         
    // This example uses a cursor to step through the
    // message queues and list the public queues on the
    // network that specify certain criteria.
    //**************************************************
    public static void main(String[] args)
    {
        // Create a new instance of the class.
        MyNewQueue myNewQueue = new MyNewQueue();
        // Output the count of Lowest priority messages.
        myNewQueue.ListPublicQueuesByCriteria();
        return;
    } //main

    //**************************************************
    // Iterates through message queues and displays the
    // path of each queue that was created in the last
    // day and that exists on the computer "MyComputer". 
    //**************************************************
    public void ListPublicQueuesByCriteria()
    {
        long numberQueues = 0;        
        // Specify the criteria to filter by.
        MessageQueueCriteria myCriteria = new MessageQueueCriteria();
        myCriteria.set_MachineName("MyComputer");
        myCriteria.set_CreatedAfter(DateTime.get_Now().
            Subtract(new TimeSpan(1, 0, 0, 0)));
        // Get a cursor into the queues on the network.
        MessageQueueEnumerator myQueueEnumerator =
            MessageQueue.GetMessageQueueEnumerator(myCriteria);
        // Move to the next queue and read its path.
        while (myQueueEnumerator.MoveNext()) {
            // Increase the count if priority is Lowest.
            Console.WriteLine(myQueueEnumerator.get_Current().get_Path());
            numberQueues++;
        }
        // Handle no queues matching the criteria.
        if (numberQueues == 0) {
            Console.WriteLine("No public queues match criteria.");
        }
        return;
    } //ListPublicQueuesByCriteria
} //MyNewQueue

System.Object
  System.Messaging.MessageQueueCriteria

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

Community Additions

ADD
Show:
© 2014 Microsoft