Error executing template "Designs/Swift/Navigation/Custom_BreadcrumbNavigation.cshtml"
System.InvalidOperationException: Sequence contains no elements
   at System.Linq.Enumerable.First[TSource](IEnumerable`1 source)
   at CompiledRazorTemplates.Dynamic.RazorEngine_4a1b820213984f8cb356e5221ba5fe93.Execute() in D:\dynamicweb.net\Solutions\Novicell\danitech.cloud.dynamicweb-cms.com\Files\Templates\Designs\Swift\Navigation\Custom_BreadcrumbNavigation.cshtml:line 20
   at RazorEngine.Templating.TemplateBase.RazorEngine.Templating.ITemplate.Run(ExecuteContext context, TextWriter reader)
   at RazorEngine.Templating.RazorEngineService.RunCompile(ITemplateKey key, TextWriter writer, Type modelType, Object model, DynamicViewBag viewBag)
   at RazorEngine.Templating.RazorEngineServiceExtensions.<>c__DisplayClass16_0.<RunCompile>b__0(TextWriter writer)
   at RazorEngine.Templating.RazorEngineServiceExtensions.WithWriter(Action`1 withWriter)
   at Dynamicweb.Rendering.RazorTemplateRenderingProvider.Render(Template template)
   at Dynamicweb.Rendering.TemplateRenderingService.Render(Template template)
   at Dynamicweb.Rendering.Template.RenderRazorTemplate()


  1     @using Dynamicweb.Ecommerce.ProductCatalog
  2     @using Dynamicweb.Frontend
  3     @using Dynamicweb.Frontend.Navigation
  4     @inherits Dynamicweb.Rendering.ViewModelTemplate<Dynamicweb.Frontend.Navigation.NavigationTreeViewModel>
  5     @{
  6         var nodes = Model.Nodes;
  7         var isProduct = false;
  8         var productName = string.Empty;
  9     
 10         IList<string> productGroupPathIdList = null;
 11     
 12         if (Dynamicweb.Context.Current.Items.Contains("ProductDetails") && Dynamicweb.Context.Current.Items["ProductDetails"] is ProductViewModel product)
 13         {
 14             var navigationSettings = new NavigationSettings();
 15             navigationSettings.StartLevel = 0;
 16             navigationSettings.StopLevel = 100;
 17             navigationSettings.RootPageId = Pageview.Area.UrlName.ToLower().Contains("en") ? 1690 : 1376;
 18             navigationSettings.ExpandMode = ExpandMode.All;
 19     
 20             var productGroupPath = product.GroupPaths.First();
 21             if (productGroupPath != null)
 22             {
 23                 productGroupPathIdList = productGroupPath.Select(c => c.Id).ToList();
 24                 nodes = Navigation.GetNavigationViewModel(navigationSettings).Nodes;
 25     
 26                 isProduct = true;
 27                 productName = product.Name;
 28             }
 29         }
 30     }
 31     
 32     @if (!Pageview.IsVisualEditorMode)
 33     {
 34         string menuId = Model.Parameters.ContainsKey("menu-id") ? $"menu_{Model.Parameters["menu-id"].ToString().ToLower()}" : string.Empty;
 35         <nav>
 36             <ol class="breadcrumb small mb-0 @menuId">
 37                 @if (isProduct)
 38                 {
 39                     var firstNode = Model.Nodes.FirstOrDefault();
 40                     if (firstNode != null)
 41                     {
 42                         <li class="breadcrumb-item">
 43                             <a href="@firstNode.Link">@firstNode.Name</a>
 44                         </li>
 45                     }
 46     
 47                     @RenderNodesByProduct(nodes, productGroupPathIdList)
 48     
 49                     <li class="breadcrumb-item active">
 50                         @productName
 51                     </li>
 52                 }
 53                 else
 54                 {
 55                     @RenderNodes(nodes)
 56                 }
 57             </ol>
 58         </nav>
 59     }
 60     else if (Model.Nodes.Count() == 0)
 61     {
 62         <div class="alert alert-dark m-0" role="alert">
 63             <span>@Translate("Breadcrumb navigation: The navigation will be shown here, if any")</span>
 64         </div>
 65     }
 66     
 67     @helper RenderNodes(IEnumerable<Dynamicweb.Frontend.Navigation.NavigationTreeNodeViewModel> nodes)
 68     {
 69         foreach (var node in nodes)
 70         {
 71             if (node.ShowInBreadcrumb)
 72             {
 73                 if (!string.IsNullOrEmpty(node.Link))
 74                 {
 75                     <li class="breadcrumb-item">
 76                         <a href="@node.Link">
 77                             @node.Name
 78                         </a>
 79                     </li>
 80                 }
 81                 else
 82                 {
 83                     <li class="breadcrumb-item">
 84                         @node.Name
 85                     </li>
 86                 }
 87                 @RenderNodes(node.Nodes)
 88             }
 89         }
 90     }
 91     @helper RenderNodesByProduct(IEnumerable<NavigationTreeNodeViewModel> nodes, IList<string> productGroupPathIdList)
 92     {
 93         foreach (var node in nodes)
 94         {
 95             if (productGroupPathIdList.Contains(node.GroupId))
 96             {
 97                     <li class="breadcrumb-item">
 98                         <a href="@node.Link">@node.Name</a>
 99                     </li>
100     
101                     @RenderNodesByProduct(node.Nodes, productGroupPathIdList)
102             }
103         }
104     }
105