private async Task ShowExistingWebResources(Guid?lastLinkedWebResource = null)
        {
            if (!this.IsControlsEnabled)
            {
                return;
            }

            ToggleControls(false, Properties.WindowStatusStrings.LoadingWebResources);

            this.trVWebResources.Dispatcher.Invoke(() =>
            {
                this.trVWebResources.ItemsSource = null;
                this.trVWebResources.Items.Clear();
            });

            string textName = string.Empty;

            txtBFilter.Dispatcher.Invoke(() =>
            {
                textName = txtBFilter.Text.Trim().ToLower();
            });

            List <WebResource> list = null;

            WebResourceRepository repository = new WebResourceRepository(this._service);

            try
            {
                list = await repository.GetListAllAsync(textName, new ColumnSet(WebResource.Schema.Attributes.name, WebResource.Schema.Attributes.webresourcetype, WebResource.Schema.Attributes.ismanaged, WebResource.Schema.Attributes.ishidden));

                if (lastLinkedWebResource.HasValue && this._lastWebResource == null)
                {
                    this._lastWebResource = await repository.GetByIdAsync(lastLinkedWebResource.Value);

                    string name = this._lastWebResource?.Name;

                    bool isEnabled = this._lastWebResource != null;

                    Visibility visibility = isEnabled ? Visibility.Visible : Visibility.Collapsed;

                    this.Dispatcher.Invoke(() =>
                    {
                        txtBLastLink.Text = name;

                        btnSelectLastLink.IsEnabled  = lblLastLink.IsEnabled = txtBLastLink.IsEnabled = sepLastLink.IsEnabled = isEnabled;
                        btnSelectLastLink.Visibility = lblLastLink.Visibility = txtBLastLink.Visibility = sepLastLink.Visibility = visibility;

                        toolStrip.UpdateLayout();
                    });
                }
            }
            catch (Exception ex)
            {
                this._iWriteToOutput.WriteErrorToOutput(_service.ConnectionData, ex);

                list = new List <WebResource>();
            }

            LoadWebResources(list);

            ToggleControls(true, Properties.WindowStatusStrings.LoadingWebResourcesCompletedFormat1, list.Count());
        }