private void btConsultar_Click(object sender, RoutedEventArgs e)
 {
     try
     {
         if (((RequisicaoInternaCabecalhoViewModel)DataContext).RequisicaoInternaDetalheSelected != null)
         {
             tabDetalhe.IsSelected = true;
             RequisicaoInternaDetalhe viewDetalhe = new RequisicaoInternaDetalhe();
             viewDetalhe.btSair.Click   += new RoutedEventHandler(btSair_Click);
             viewDetalhe.btGravar.Click += new RoutedEventHandler(btGravar_Click);
             tabDetalhe.Content          = viewDetalhe;
         }
         else
         {
             MessageBox.Show("Selecione um elemento na lista.", "Alerta do sistema");
         }
     }
     catch (Exception ex)
     {
         throw ex;
     }
 }