// es obligatorio que sea publico!
 public void OnCopyDataReceived(MyCopyData copyData)
 {
     this.recepcion.Text = copyData.CopyString;
 }
        void EventAgregatorCopy_Click(object sender, System.Windows.RoutedEventArgs e)
        {

            TheEventAggregator = ServiceLocator.Current.GetInstance<IEventAggregator>();
            // get a reference to the event from 
            // the event aggregator
            CompositePresentationEvent<MyCopyData> myCopyEvent =
                TheEventAggregator.GetEvent<MyCopyDataAddedEvent>();

            // get the data text from TheTextToCopyTextBox TextBox control
            MyCopyData copyData = new MyCopyData
            {
                CopyString = Parametro1.Text
            };

            //publish data via event aggregator
            myCopyEvent.Publish(copyData);
        }