MessageQueue.GetMessageEnumerator 方法

定義

命名空間:

System.Messaging

組件:

System.Messaging.dll

警告

This method returns a MessageEnumerator that implements RemoveCurrent family of methods incorrectly. Please use GetMessageEnumerator2 instead.

為佇列中的所有訊息建立列舉值物件。 GetMessageEnumerator() 已被取代。 應改用 GetMessageEnumerator2()。

public:
 System::Messaging::MessageEnumerator ^ GetMessageEnumerator();

[System.Obsolete("This method returns a MessageEnumerator that implements RemoveCurrent family of methods incorrectly. Please use GetMessageEnumerator2 instead.")]
public System.Messaging.MessageEnumerator GetMessageEnumerator ();

[<System.Obsolete("This method returns a MessageEnumerator that implements RemoveCurrent family of methods incorrectly. Please use GetMessageEnumerator2 instead.")>]
member this.GetMessageEnumerator : unit -> System.Messaging.MessageEnumerator

Public Function GetMessageEnumerator () As MessageEnumerator

傳回

MessageEnumerator

MessageEnumerator，保有在佇列中所包含的訊息。

屬性

ObsoleteAttribute

範例

下列程式代碼範例會取得佇列中的訊息動態清單，並計算屬性設定為 MessagePriority.Lowest的所有訊息Priority。

#using <system.dll>
#using <system.messaging.dll>

using namespace System;
using namespace System::Messaging;
ref class MyNewQueue
{
public:
   void CountLowestPriority()
   {
      
      // Holds the count of Lowest priority messages.
      UInt32 numberItems = 0;
      
      // Connect to a queue.
      MessageQueue^ myQueue = gcnew MessageQueue( ".\\myQueue" );
      
      // Get a cursor into the messages in the queue.
      MessageEnumerator^ myEnumerator = myQueue->GetMessageEnumerator();
      
      // Specify that the messages's priority should be read.
      myQueue->MessageReadPropertyFilter->Priority = true;
      
      // Move to the next message and examine its priority.
      while ( myEnumerator->MoveNext() )
      {
         
         // Increase the count if priority is Lowest.
         if ( myEnumerator->Current->Priority == MessagePriority::Lowest )
                  numberItems++;
      }

      
      // Display final count.
      Console::WriteLine( "Lowest priority messages: {0}", numberItems );
      return;
   }

};

int main()
{
   
   // Create a new instance of the class.
   MyNewQueue^ myNewQueue = gcnew MyNewQueue;
   
   // Output the count of Lowest priority messages.
   myNewQueue->CountLowestPriority();
   return 0;
}

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
        // messages in a queue and counts the number of
        // Lowest priority messages.
        //**************************************************

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

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

        //**************************************************
        // Iterates through messages in a queue and examines
        // their priority.
        //**************************************************
        
        public void CountLowestPriority()
        {
            // Holds the count of Lowest priority messages.
            uint numberItems = 0;

            // Connect to a queue.
            MessageQueue myQueue = new MessageQueue(".\\myQueue");
    
            // Get a cursor into the messages in the queue.
            MessageEnumerator myEnumerator =
                myQueue.GetMessageEnumerator();

            // Specify that the messages's priority should be read.
            myQueue.MessageReadPropertyFilter.Priority = true;

            // Move to the next message and examine its priority.
            while(myEnumerator.MoveNext())
            {
                // Increase the count if priority is Lowest.
                if(myEnumerator.Current.Priority ==
                    MessagePriority.Lowest)
                    
                    numberItems++;
            }

            // Display final count.
            Console.WriteLine("Lowest priority messages: " +
                numberItems.ToString());
            
            return;
        }
    }
}

Imports System.Messaging

Public Class MyNewQueue


        
        ' Provides an entry point into the application.
        '		 
        ' This example uses a cursor to step through the
        ' messages in a queue and counts the number of 
        ' Lowest priority messages.
        

        Public Shared Sub Main()

            ' Create a new instance of the class.
            Dim myNewQueue As New MyNewQueue()

            ' Output the count of Lowest priority messages.
            myNewQueue.CountLowestPriority()

            Return

        End Sub


        
        ' Iterates through messages in a queue and examines
        ' their priority.
        

        Public Sub CountLowestPriority()

            ' Holds the count of Lowest priority messages.
            Dim numberItems As Int32 = 0

            ' Connect to a queue.
            Dim myQueue As New MessageQueue(".\myQueue")

            ' Get a cursor into the messages in the queue.
            Dim myEnumerator As MessageEnumerator = _
                myQueue.GetMessageEnumerator()

            ' Specify that the messages's priority should be read.
            myQueue.MessageReadPropertyFilter.Priority = True

            ' Move to the next message and examine its priority.
            While myEnumerator.MoveNext()

                ' Increase the count if the priority is Lowest.
                If myEnumerator.Current.Priority = _
                    MessagePriority.Lowest Then
                    numberItems += 1
                End If

            End While

            ' Display final count.
            Console.WriteLine(("Lowest priority messages: " + _
                numberItems.ToString()))

            Return

        End Sub

End Class

備註

GetMessageEnumerator 會建立佇列中所有訊息的動態清單。 您可以呼叫 RemoveCurrentMessageEnumeratorGetMessageEnumerator 傳回的 ，從佇列中移除位於列舉值目前位置的訊息。

由於數據指標與佇列中的訊息動態清單相關聯，因此如果訊息超出目前的數據指標位置，列舉會反映對佇列中訊息所做的任何修改。 例如，列舉值可以自動存取置於游標目前位置以外的較低優先順序訊息，但無法自動存取在該位置之前插入的較高優先順序訊息。 不過，您可以藉由呼叫 ResetMessageEnumerator來重設列舉，藉此將游標移回清單的開頭。

列舉中的訊息順序會反映其在佇列中的順序，因此優先順序較高的訊息會出現在優先順序較低的訊息之前。

如果您要佇列中訊息的靜態快照集，而不是與其動態連線，請呼叫 GetAllMessages。 這個方法會傳回 物件的陣列，這個陣列 Message 表示呼叫方法時所傳回的訊息。

下表顯示此方法是否可在各種工作組模式中使用。

工作組模式	可用
本機電腦	是
本機計算機和直接格式名稱	是
遠端電腦	是
遠端電腦和直接格式名稱	是

另請參閱

• GetAllMessages()
• GetMessageEnumerator2()
• GetMessageQueueEnumerator()