Change datasource in final layout through API

Question

I am trying to add some code (after an item is created - but that is not relevant) that manipulates the layout fields. To be precise, I want to change the datasource of some renderings (based on a few criteria). My problem is that I would like to do this for both shared and final layout.

My code for the shared layout is working. It is based on var layout = LayoutDefinition.Parse(item[Sitecore.FieldIDs.LayoutField]); which gives me the LayoutDefinition. I can loop over all devices, all renderings and change the datasources. When something changed, I edit the item and overwrite the layout field with the new value that I get with layout.ToXml().

So I thought/hoped I could do the same with the Sitecore.FieldIDs.FinalLayoutField. But that seems not the case. When parsed, the LayoutDefinition from the final layout field is quite different from the actual value. Does anyone have an idea why? And how I can get around this?

ps: I did consider using the actual xml value and parsing it, but that does seem like such an ugly solution..

Edit: the actual values I'm working with:

• Raw value of final rendering:

<r xmlns:p="p" xmlns:s="s" p:p="1"><d id="{FE5D7FDF-89C0-4D99-9AA3-B5FBD009C9F3}">
  <r uid="{9B197064-13D1-4BB6-AD47-2F770696404E}" p:after="r[@uid='{A6059F4C-2B62-4640-8723-BA7C87AA13D1}']" s:ds="{A419D90D-2315-4096-BECE-67AB3CDF6566}" s:id="{00160D4B-055D-4C4F-B8F1-D4E55B072294}" s:ph="/main/content2{b1ff55e7-8288-45c0-9994-f7eec00d56fc}" />
  <r uid="{6DD5BA3B-73E1-4F7A-A0EF-F2FB45F3A79F}" s:ds="{A419D90D-2315-4096-BECE-67AB3CDF6566}" s:par="" />
</d></r>

• Value of item[Sitecore.FieldIDs.FinalLayoutField]:

<r xmlns:p=\"p\" xmlns:s=\"s\" p:p=\"1\"><d id=\"{FE5D7FDF-89C0-4D99-9AA3-B5FBD009C9F3}\">
  <r uid=\"{9B197064-13D1-4BB6-AD47-2F770696404E}\" p:after=\"r[@uid='{A6059F4C-2B62-4640-8723-BA7C87AA13D1}']\" s:ds=\"{A419D90D-2315-4096-BECE-67AB3CDF6566}\" s:id=\"{00160D4B-055D-4C4F-B8F1-D4E55B072294}\" s:ph=\"/main/content2{b1ff55e7-8288-45c0-9994-f7eec00d56fc}\" />
  <r uid=\"{6DD5BA3B-73E1-4F7A-A0EF-F2FB45F3A79F}\" s:ds=\"{A419D90D-2315-4096-BECE-67AB3CDF6566}\" s:par=\"\" />
</d></r>

Which seems to match my raw value...

• Value of LayoutDefinition.Parse(item[Sitecore.FieldIDs.FinalLayoutField]):

<r xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\"  p:p=\"1\" xmlns:p=\"p\"><d id=\"{FE5D7FDF-89C0-4D99-9AA3-B5FBD009C9F3}\" /></r>

Where are my renderings??

Answer 1

Think your problem occurs because of how the layout API works https://doc.sitecore.net/sitecore_experience_platform/developing/developing_with_sitecore/versioned_layouts/the_versioned_layout_api_changes

From the article:

Prior to Sitecore 8, the public static string GetFieldValue([NotNull] Field field) method only returned layout data from the shared __Renderings field. In Sitecore 8 and later, this method can return layout data either from the shared __Renderings field or from the versioned __Final Renderings field.

The method does not return the raw value of the field. It uses the layout patching workflow to calculate the resulting layout, and it returns this layout.

This goes both for the "getter" and "setter" and also impacts on the constructor.

Not sure if this completly covers your issue, but it is definitely where you should start.

Answer 2

Final Renderings field is a delta from the Shared renderings. This article https://www.cognifide.com/our-blogs/sitecore/complex-layouts-in-sitecore-using-standard-values-hierarchy/ includes code that works with the deltas.

This isn't a 100% match for your particular problem, but it shows the mechanics that I think match your solution.