Vergelijkbare concerten

System.NullReferenceException: Object reference not set to an instance of an object.
   at Umbraco.Core.Models.PublishedContent.PublishedContentWrapped.GetProperty(String alias, Boolean recurse)
   at Umbraco.Web.PublishedContentExtensions.GetPropertyValue[T](IPublishedContent content, String alias, Boolean recurse, Boolean withDefaultValue, T defaultValue)
   at Umbraco.Web.PublishedContentExtensions.GetPropertyValue[T](IPublishedContent content, String alias)
   at Umbraco.Extensions.Models.Generated.ProductionPage.get_SimilarEvents() in C:\InControlSwapSpace\Export\dca47629-307d-4611-af23-a2551c670307\Libraries\OudeMuziek.Extensions\Models\Generated\ProductionPage.generated.cs:line 90
   at ASP._Page_Views_Partials_Grid_Editors_DocTypeGridEditor_widgetShowSimilarConcerts_cshtml.Execute() in c:\Services\Websites\OudeMuziek2017_Website\Website\wwwroot_111\Views\Partials\Grid\Editors\DocTypeGridEditor\widgetShowSimilarConcerts.cshtml:line 18
   at System.Web.WebPages.WebPageBase.ExecutePageHierarchy()
   at System.Web.Mvc.WebViewPage.ExecutePageHierarchy()
   at System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage)
   at Umbraco.Core.Profiling.ProfilingView.Render(ViewContext viewContext, TextWriter writer)
   at System.Web.Mvc.Html.PartialExtensions.Partial(HtmlHelper htmlHelper, String partialViewName, Object model, ViewDataDictionary viewData)
   at Our.Umbraco.DocTypeGridEditor.Web.Extensions.HtmlHelperExtensions.RenderDocTypeGridEditorItem(HtmlHelper helper, IPublishedContent content, String editorAlias, String viewPath, String previewViewPath)
   at ASP._Page_app_plugins_doctypegrideditor_render_doctypegrideditor_cshtml.Execute() in c:\Services\Websites\OudeMuziek2017_Website\Website\wwwroot_111\App_Plugins\DocTypeGridEditor\Render\DocTypeGridEditor.cshtml:line 28
   at System.Web.WebPages.WebPageBase.ExecutePageHierarchy()
   at System.Web.Mvc.WebViewPage.ExecutePageHierarchy()
   at System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage)
   at Umbraco.Core.Profiling.ProfilingView.Render(ViewContext viewContext, TextWriter writer)
   at System.Web.Mvc.Html.PartialExtensions.Partial(HtmlHelper htmlHelper, String partialViewName, Object model, ViewDataDictionary viewData)
   at ASP._Page_Views_Partials_grid_editors_base_cshtml.Execute() in c:\Services\Websites\OudeMuziek2017_Website\Website\wwwroot_111\Views\Partials\Grid\Editors\Base.cshtml:line 19