MessageQueue::Receive Method (TimeSpan)

 

Receives the first message available in the queue referenced by the MessageQueue and waits until either a message is available in the queue, or the time-out expires.

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

public:
Message^ Receive(
	TimeSpan timeout
)

Parameters

timeout
Type: System::TimeSpan

A TimeSpan that indicates the time to wait until a new message is available for inspection.

Return Value

Type: System.Messaging::Message^

A Message that references the first message available in the queue.

Exception Condition
ArgumentException

The value specified for the timeout parameter is not valid, possibly timeout is less than TimeSpan::Zero or greater than MessageQueue::InfiniteTimeout.

MessageQueueException

A message did not arrive in the queue before the time-out expired.

-or-

An error occurred when accessing a Message Queuing method

.NET Framework
Available since 1.1

The method is not thread safe.

Use this overload to receive a message and return in a specified period of time if there are no messages in the queue.

The Receive method allows for the synchronous reading of a message, removing it from the queue. Subsequent calls to Receive will return the messages that follow in the queue, or new, higher priority messages.

To read the first message in a queue without removing it from the queue, use the Peek method. The Peek method always returns the first message in the queue, so subsequent calls to the method return the same message unless a higher priority message arrives in the queue.

Use a call to Receive when it is acceptable for the current thread to be blocked while it waits for a message to arrive in the queue. The thread will be blocked for the given period of time, or indefinitely if you specified the value InfiniteTimeout for the timeout parameter. If the application processing should continue without waiting for a message, consider using the asynchronous method, BeginReceive.

The following table shows whether this method is available in various Workgroup modes.

Workgroup mode

Available

Local computer

Yes

Local computer and direct format name

Yes

Remote computer

No

Remote computer and direct format name

Yes

The following code example receives a message from a queue and outputs information about that message to the screen. The example pauses execution for up to five seconds while waiting for a message to arrive in the queue.

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

using namespace System;
using namespace System::Messaging;

// This class represents an object the following example 
// receives from a queue.
ref class Order
{
public:
   int orderId;
   DateTime orderTime;
};


/// <summary>
/// Provides a container class for the example.
/// </summary>
ref class MyNewQueue
{
public:

   //*************************************************
   // Receives a message containing an Order.
   //*************************************************
   void ReceiveMessage()
   {
      // Connect to the a queue on the local computer.
      MessageQueue^ myQueue = gcnew MessageQueue( ".\\myQueue" );

      // Set the formatter to indicate body contains an Order.
      array<Type^>^p = gcnew array<Type^>(1);
      p[ 0 ] = Order::typeid;
      myQueue->Formatter = gcnew XmlMessageFormatter( p );
      try
      {
         // Receive and format the message. 
         // Wait 5 seconds for a message to arrive.
         Message^ myMessage = myQueue->Receive( TimeSpan(0,0,5) );
         Order^ myOrder = static_cast<Order^>(myMessage->Body);

         // Display message information.
         Console::WriteLine( "Order ID: {0}", myOrder->orderId );
         Console::WriteLine( "Sent: {0}", myOrder->orderTime );
      }
      catch ( MessageQueueException^ e ) 
      {
         // Handle no message arriving in the queue.
         if ( e->MessageQueueErrorCode == MessageQueueErrorCode::IOTimeout )
         {
            Console::WriteLine( "No message arrived in queue." );
         }

         // Handle other sources of a MessageQueueException.
      }
      // Handle invalid serialization format.
      catch ( InvalidOperationException^ e ) 
      {
         Console::WriteLine( e->Message );
      }

      // Catch other exceptions as necessary.
      return;
   }
};

//*************************************************
// Provides an entry point into the application.
//         
// This example receives a message from a queue.
//*************************************************
int main()
{
   // Create a new instance of the class.
   MyNewQueue^ myNewQueue = gcnew MyNewQueue;

   // Receive a message from a queue.
   myNewQueue->ReceiveMessage();
   return 0;
}
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