The MessageQueue property returns an ObservableCollection of strings for the messages sent by the runtime system as a response to a colon command. You can register for the CollectionChanged event on an ObservableCollection that notifies the client when an update has been performed on the collection; that is, when a new message has been received from the host application.

Namespace – ABSuite.AccessLayer.Connector.Core

Assembly – Unisys.ABSuite.AccessLayer.Connector.Core (in Unisys.ABSuite.AccessLayer.Connector.Core.dll)

Syntax

IEnumerable<string> MessageQueue { get; }

Using the IUnsolicitedMessages Interface for the MessageQueue Property

The following code is an example of using the MessageQueue property for handling command responses:

// Declare a StringBuilder to hold the Command Responses
    CommandResponesBuilder = new StringBuilder();

    // Register for the CollectionChanged event for notification of 
   // new messages 

    ABSConnection.MessagesHandler.MessageQueue.CollectionChanged += (o, e) =>
    {
        this.QueueUpdate(e, ABSConnection.MessagesHandler.MessageQueue, this.CommandResponesBuilder);
    };
   // The QueueUpdate method handles changes in the 
  // ObeservableCollection of command and video report responses. 
 // When a message arrives, it is added to the 
// StringBuilder parameter. 
    // If the Collection is Reset, the StringBuilder parameter is 
   // cleared and new messages are added.
private void QueueUpdate(NotifyCollectionChangedEventArgs e, IList<string> items, StringBuilder builder)
    {
        switch (e.Action)
        {
            case NotifyCollectionChangedAction.Add:
                if (e.NewItems != null)
                {
                    foreach (string item in e.NewItems)
                    {
                        if (item.Trim() == ">")
                            builder.Append(item);
                        else
                            builder.AppendLine(item);
                    }                 
                }
                break;
            case NotifyCollectionChangedAction.Remove:
            case NotifyCollectionChangedAction.Replace:
                break;
 
            case NotifyCollectionChangedAction.Reset:
            {
                builder.Clear();
                foreach (string item in items)
                    builder.AppendLine(item);
            }
            break;
        }
    }