Error executing template "/Designs/Swift-v2/Paragraph/Swift-v2_RelatedProductsList_Custom.cshtml"
System.ArgumentNullException: Value cannot be null. (Parameter 'source')
   at System.Linq.ThrowHelper.ThrowArgumentNullException(ExceptionArgument argument)
   at System.Linq.Enumerable.SelectMany[TSource,TResult](IEnumerable`1 source, Func`2 selector)
   at CompiledRazorTemplates.Dynamic.RazorEngine_2e8b3993e0b249cb80975f535f243e94.ExecuteAsync()
   at RazorEngine.Templating.TemplateBase.Run(ExecuteContext context, TextWriter reader)
   at RazorEngine.Templating.RazorEngineCore.RunTemplate(ICompiledTemplate template, TextWriter writer, Object model, DynamicViewBag viewBag)
   at RazorEngine.Templating.RazorEngineService.Run(ITemplateKey key, TextWriter writer, Type modelType, Object model, DynamicViewBag viewBag)
   at RazorEngine.Templating.DynamicWrapperService.Run(ITemplateKey key, TextWriter writer, Type modelType, Object model, DynamicViewBag viewBag)
   at RazorEngine.Templating.RazorEngineServiceExtensions.Run(IRazorEngineService service, String name, TextWriter writer, Type modelType, Object model, DynamicViewBag viewBag)
   at RazorEngine.Templating.RazorEngineServiceExtensions.<>c__DisplayClass23_0.<Run>b__0(TextWriter writer)
   at RazorEngine.Templating.RazorEngineServiceExtensions.WithWriter(Action`1 withWriter)
   at RazorEngine.Templating.RazorEngineServiceExtensions.Run(IRazorEngineService service, String name, Type modelType, Object model, DynamicViewBag viewBag)
   at Dynamicweb.Rendering.RazorTemplateRenderingProvider.Render(Template template)
   at Dynamicweb.Rendering.TemplateRenderingService.Render(Template template)
   at Dynamicweb.Rendering.Template.RenderRazorTemplate()


  1     @inherits Dynamicweb.Rendering.ViewModelTemplate<Dynamicweb.Frontend.ParagraphViewModel>
  2     @using Dynamicweb.Ecommerce.ProductCatalog
  3     @using Dynamicweb.Frontend
  4     
  5     @{
  6     	ProductViewModel product = new ProductViewModel();
  7     
  8     	if (Dynamicweb.Context.Current.Items.Contains("ProductDetails"))
  9     	{
 10     		product = (ProductViewModel)Dynamicweb.Context.Current.Items["ProductDetails"];
 11     	}
 12     
 13     	string servicePageId = Model.Item.GetLink("ServicePage") != null ? Model.Item.GetLink("ServicePage").PageId.ToString() : "";
 14     	servicePageId = servicePageId == "" && GetPageIdByNavigationTag("RelatedProductsListService_Custom") != 0 ? GetPageIdByNavigationTag("RelatedProductsListService_Custom").ToString() : servicePageId;
 15     	string pageSize = Model.Item.GetInt32("PageSize") != 0 ? Model.Item.GetString("PageSize") : "10";
 16     
 17     	string title = !string.IsNullOrEmpty(Model.Item.GetString("Title")) ? Model.Item.GetString("Title") : "";
 18     	string hideTitle = Model.Item.GetBoolean("HideTitle").ToString();
 19     	string hideImage = Model.Item.GetBoolean("HideImage").ToString();
 20     	string hideProductNumber = Model.Item.GetBoolean("HideProductNumber").ToString();
 21     	string hideProductName = Model.Item.GetBoolean("HideProductName").ToString();
 22     	string titleFontSize = Model.Item.GetRawValueString("TitleFontSize", "display-6");
 23     
 24     	// Product type filter — comma-separated group IDs selected in Visual Editor
 25     	IEnumerable<string> productTypeFilter = Model.Item.GetList("ProductTypeFilter")?.GetRawValue().OfType<string>().ToList() ?? new List<string>();
 26     	string productTypeFilterString = productTypeFilter.Any() ? string.Join(",", productTypeFilter) : "";
 27     
 28     	string productIds = string.Join(",", product.RelatedGroups
 29     		.SelectMany(g => g.Products)
 30     		.Select(p => string.IsNullOrEmpty(p.VariantId) ? p.ProductId : $"{p.ProductId} {p.VariantId}")
 31     		.Where(s => !string.IsNullOrEmpty(s)));
 32     }
 33     
 34     @if (!Pageview.IsVisualEditorMode)
 35     {
 36     	<div id="RelatedProductsListCustomContainer_@Pageview.CurrentParagraph.ID"
 37          class="item_@Model.Item.SystemName.ToLower()" @(productIds.Count() == 0 ? "hidden" : "")>
 38     		<form action="/Default.aspx?ID=@servicePageId" id="RelatedProductsListCustomForm_@Pageview.CurrentParagraph.ID" data-response-target-element="RelatedProductsListCustomContainer_@Pageview.CurrentParagraph.ID">
 39     			<input type="hidden" name="ID" value="@servicePageId">
 40     			<input type="hidden" name="SourceType" value="related-products">
 41     			<input type="hidden" name="ParagraphID" value="@Pageview.CurrentParagraph.ID">
 42     			<input type="hidden" name="PageSize" value="@pageSize" id="RelatedProductsListCustomPageSize_@Pageview.CurrentParagraph.ID">
 43     			<input type="hidden" name="PageSizeSetting" value="@pageSize">
 44     			<input type="hidden" name="Title" value="@title">
 45     			<input type="hidden" name="HideTitle" value="@hideTitle">
 46     			<input type="hidden" name="HideImage" value="@hideImage">
 47     			<input type="hidden" name="HideProductNumber" value="@hideProductNumber">
 48     			<input type="hidden" name="HideProductName" value="@hideProductName">
 49     			<input type="hidden" name="TitleFontSize" value="@titleFontSize">
 50     			<input type="hidden" name="ProductTypeFilter" value="@productTypeFilterString">
 51     			<input type="hidden" name="ProductvariantId" value="@productIds">
 52     		</form>
 53     	</div>
 54     
 55     	<script type="module">
 56     		swift.PageUpdater.Update(document.querySelector("#RelatedProductsListCustomForm_@Pageview.CurrentParagraph.ID"));
 57     	</script>
 58     
 59     	<script>
 60     		var UpdateRelatedProductsListCustom = function(event, id) {
 61     			document.querySelector('#RelatedProductsListCustomForm_' + id).setAttribute("data-response-target-element", "RelatedProductsListCustomContainer_" + id);
 62     			swift.PageUpdater.Update(document.querySelector("#RelatedProductsListCustomForm_" + id));
 63     		};
 64     	</script>
 65     }
 66     else
 67     {
 68     	<div class="alert alert-info" role="alert">
 69     		<span>@Translate("Related products list")</span>
 70     		@if (!string.IsNullOrEmpty(title))
 71     		{
 72     			<strong> — @title</strong>
 73     		}
 74     	</div>
 75     }
 76