Note – this is applicable to both SharePoint 2010 and SharePoint 2013 .. and despite rumours of “The Sandbox is deprecated” many features in SharePoint 2013 rely on the Sandbox so I don’t see it going anywhere for the time being
This is something that I have been told many times, it is not possible to embed a server control developed in the Sandbox onto a Page Layout or Master Page because you can’t add the appropriate Tag Prefix to the header.
If you consider the standard way of doing this for a Farm / Full Trust solution:
<% @Register TagPrefix="MJH" Namespace="MJH.Examples.WebControls" Assembly="MJH.Examples, Version=126.96.36.199, Culture=neutral, PublicKeyToken=16e05f568fffc0d1" %> <!-- Custom Web Control--> <MJH:SampleCustomControl runat="server" />
In the sandbox we obviously can’t reference the Assembly in the same way because (a) it isn’t deployed to the GAC / BIN folders and (b) it runs in a completely different process so won’t be JIT compiled by the .Net Framework… but there is a solution!
Microsoft.SharePoint.WebPartPages.SPUserCodeWebPart allows you to embed a Web Part from an assembly running in the Sandbox.
<!-- custom sandbox web part --> <WebPartPages:SPUserCodeWebPart runat="server" AssemblyFullName="MJH.Examples.Sandbox, Version=188.8.131.52, Culture=neutral, PublicKeyToken=60d6fc7a560ae45c" SolutionId="4faf8ff6-36ea-406f-af25-4d89472a41e1" TypeFullName="MJH.Examples.Sandbox.WebParts.SampleCustomControl" > </WebPartPages:SPUserCodeWebPart>
You still need the “AssemblyFullName” attribute. I’ve found the easy way to get this is to add a feature receiver to a Feature in Visual Studio then copy-paste it from the Manifest in Visual Studio (which contains the full text that you need).
So thats it! Happy coding