Skip to main content

A DD4T.net Implementation - Get the Page Model from Component Presentation

It is possible to retrieve the IPage model object from a Component Presentation context. Whether this is a good practice or not, I'm not going to debate it here. In case you need the IPage object, this is how to get it.

From Component Controller

The simplest way to retrieve the IPage model is to have your Component controllers extend TridionControllerBase, then call base method GetComponentPresentation().

The returned object contains a property Page, which gets the IPage model.

This however doesn't always work, namely when the Component Presentation is dynamic is doesn't actually reside on the page.

public class DeviceController : TridionControllerBase
{
    public ActionResult Index()
    {
        IComponentPresentation componentPresentation = GetComponentPresentation();
        IPage page = componentPresentation.Page;

From ViewContext in Component Controller

This approach relies on the way Component Presentations are rendered by DD4T. Namely, the CPs are rendered from a context of the Page Razor view, by means of calling Html.Action behind the scenes.

This means the Component controller's property ControllerContext has knowledge of the parent ViewContext, which, through the ViewData property could give us the Model representing the IPage model. I say could, because the views and actions could be nested even further, so that it is unclear which view model will be the IPage. In this situation, one can just skip up the parent ViewContext chain until it finds an IPage model.

    public IPage GetPage()
    {
        IPage page = null;
        ViewContext context = ControllerContext.ParentActionViewContext;

        while (page == null && context != null)
        {
            page = context.ViewData.Model as IPage;
            context = context.ParentActionViewContext;
        }

        return page;
    }

From HtmlHelper Extension Method

An HtmlHelper object has access to the ViewContext of the current action. Therefore, any extension method of HtmlHelper can access this property as well.

The logic further is very similar to the previous example: one can check the ViewData.Model properties and retrieve the potential IPage model. In case the views/actions are nested further, we can skip up the ParentActionViewContext property to retrieve their model object.

    private static IPage GetPage(HtmlHelper htmlHelper)
    {
        IPage page = htmlHelper.ViewData.Model as IPage;
        if (page == null)
        {
            ViewContext context = htmlHelper.ViewContext;
            while (page == null && context != null)
            {
                page = context.ViewData.Model as IPage;
                context = context.ParentActionViewContext;
            }
        }

        return page;
    }


Comments

Popular posts from this blog

Running sp_updatestats on AWS RDS database

Part of the maintenance tasks that I perform on a MSSQL Content Manager database is to run stored procedure sp_updatestats . exec sp_updatestats However, that is not supported on an AWS RDS instance. The error message below indicates that only the sa  account can perform this: Msg 15247 , Level 16 , State 1 , Procedure sp_updatestats, Line 15 [Batch Start Line 0 ] User does not have permission to perform this action. Instead there are several posts that suggest using UPDATE STATISTICS instead: https://dba.stackexchange.com/questions/145982/sp-updatestats-vs-update-statistics I stumbled upon the following post from 2008 (!!!), https://social.msdn.microsoft.com/Forums/sqlserver/en-US/186e3db0-fe37-4c31-b017-8e7c24d19697/spupdatestats-fails-to-run-with-permission-error-under-dbopriveleged-user , which describes a way to wrap the call to sp_updatestats and execute it under a different user: create procedure dbo.sp_updstats with execute as 'dbo' as

Content Delivery Monitoring in AWS with CloudWatch

This post describes a way of monitoring a Tridion 9 combined Deployer by sending the health checks into a custom metric in CloudWatch in AWS. The same approach can also be used for other Content Delivery services. Once the metric is available in CloudWatch, we can create alarms in case the service errors out or becomes unresponsive. The overall architecture is as follows: Content Delivery service sends heartbeat (or exposes HTTP endpoint) for monitoring Monitoring Agent checks heartbeat (or HTTP health check) regularly and stores health state AWS lambda function: runs regularly reads the health state from Monitoring Agent pushes custom metrics into CloudWatch I am running the Deployer ( installation docs ) and Monitoring Agent ( installation docs ) on a t2.medium EC2 instance running CentOS on which I also installed the Systems Manager Agent (SSM Agent) ( installation docs ). In my case I have a combined Deployer that I want to monitor. This consists of an Endpoint and a

Debugging a Tridion 2011 Event System

OK, so you wrote your Tridion Event System. Now it's time to debug it. I know this is a hypothetical situtation -- your code never needs any kind of debugging ;) but indulge me... Recently, Alvin Reyes ( @nivlong ) blogged about being difficult to know how exactly to debug a Tridion Event System. More exactly, the question was " What process do I attach to for debugging even system code? ". Unfortunately, there is no simple or generic answer for it. Different events are fired by different Tridion CM modules. These modules run as different programs (or services) or run inside other programs (e.g. IIS). This means that you will need to monitor (or debug) different processes, based on which events your code handles. So the usual suspects are: dllhost.exe (or dllhost3g.exe ) - running as the MTSUser is the SDL Tridion Content Manager COM+ application and it fires events on generic TOM objects (e.g. events based on Tridion.ContentManager.Extensibility.Events.CrudEven