Hi, we have met quite unexpected problem with shared blocks.

Scenario assumes that we have shared block which provides some ContentArea with specific layout and we would like to allow users to nest itself to provide maximum flexibility in content managment.

I define this block:

    public class TwoColumnLayoutBlock : BaseLayoutBlock
    {
        [Display(
            Name = "Left Column",
            Description = "Content of left column",
            GroupName = SystemTabNames.Content,
            Order = 1)]
        public virtual ContentArea LeftColumn { get; set; }

        [Display(
            Name = "Right Column",
            Description = "Content of right column",
            GroupName = SystemTabNames.Content,
            Order = 2)]
        public virtual ContentArea RightColumn { get; set; }
    }

With default Controller and this View:

@model MyProject.Models.Layouts.TwoColumnLayoutBlock


    

        @{
            Html.RenderContentArea(Model.LeftColumn);
        }
    
    

        @{
            Html.RenderContentArea(Model.RightColumn);
        }
    

Than I create Two instances of TwoColumnLayoutBlock in CMS named "MainLayout" and "LeftColumn" and I put LeftColumn in MainLayout.LeftColumn property as content.

If I try to add MainLayout to my main page content area I get some ugly error:

   at System.ThrowHelper.ThrowInvalidOperationException(ExceptionResource resource)
   at System.Collections.Generic.Stack`1.Peek()
   at System.Web.WebPages.WebPageBase.GetOutputWriter()
   at System.Web.WebPages.WebPageExecutingBase.BeginContext(String virtualPath, Int32 startPosition, Int32 length, Boolean isLiteral)
   at ASP._Page_addons_MyProject_Views_TwoColumnLayoutBlock_Index_cshtml.Execute() in c:\work\src\myproject\Views\TwoColumnLayoutBlock\Index.cshtml:line 12
   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 System.Web.Mvc.RazorView.RenderView(ViewContext viewContext, TextWriter writer, Object instance)
   at System.Web.Mvc.BuildManagerCompiledView.Render(ViewContext viewContext, TextWriter writer)
   at System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context)
   at System.Web.Mvc.ControllerActionInvoker.InvokeActionResult(ControllerContext controllerContext, ActionResult actionResult)

I would be very grateful if someone could point me some errors in my approach. In theory there is some recurence going on, but in fact LeftColumn block does not reference any other block, so it seems a little bit strange to me.

Sincerely

Maciej Błaszczyk