private void buttonAccept_Click(object sender, RoutedEventArgs e) { buttonAccept.Visibility = Visibility.Hidden; buttonCancel.Visibility = Visibility.Hidden; buttonClose.Visibility = Visibility.Visible; WaveIn wi = new WaveIn(); wi.WaveFormat = ClientInformation.waveFormat; wi.DataAvailable += new EventHandler <WaveInEventArgs>(wi_DataAvailableCallback); audioCallback.Wi = wi; audioService.Confirmation(ClientInformation.Username, ConversationPartner, true, IsGroup); audioCallback.StartRecording(); textBlock.Text = "Audio Call with " + ConversationPartner; }