Using the SP2013 Client Object Model in InfoPath managed code

Someone asked me today about using the SharePoint 2013 Client Object Model in Managed Code.  I’ve done this in VSTA (Visual Studio for Tools and Applications) in C#.  It took a bit of experimentation to get it going, here’s how I did it:

I extracted the Client Object Model runtime DLLs from the SharePoint server.  That’s both Microsoft.SharePoint.Client.dll and Microsoft.SharePoint.Client.runtime.dll.  For good measure I also took Microsoft.SharePoint.Client.Runtime.dll.deploy

In my C# (I was using VSTA) as for Managed C# in InfoPath, I:

1. Added three project references:
   1. System.Core
   2. SharePoint.Client
   3. SharePoint.Client.Runtime
2. Added Using for SharePoint.Client

Opened AssemblyInfo.cs to deal with partial trust exception, and added:

using System.Security; //Added to try to resolve the partial trust error: JP
[assembly: AllowPartiallyTrustedCallers]   //Added to try to resolve the partial trust error: JP

I had to turn the form  from “Automatically determine security level” to “Full Trust”.  This is an InfoPath specific setting, that may affect how this runs as a Farm Solution, and whether it needs a Farm Administrators approval.

At that point, you can use the Client Object Model.  Getting data is done two different ways:

–          CAML: my native old-style preferred approach for simple queries

–          LINQ: for SQL-like queries; the one catch is you need to use SPMetal to create a runtime Thunk of sorts specific to your target sites/lists

Hope that helps!