I am having troubles to get it running and wanted to ask you if you know if it is possible to use CSOM in SP 2013 Farm Solutions?

I constantly get an 401 unauthorized exception.

Here is how I create the clientcontext:

this.webUrl = SPContext.Current.Web.Url;
this.siteUrl = SPContext.Current.Site.Url;

clientContext = new SP.ClientContext(this.webUrl);
clientContext.Credentials = CredentialCache.DefaultNetworkCredentials;

As I want to share the code between an SharePoint Autohosted app and my farm solution I have to use the CSOM.

  • Are you building a separate web application, similar to an autohosted one, that will connect to your SharePoint and you want users to be able to authenticate to SharePoint through this web application? – eirikb Apr 22 '14 at 11:31

This won't work because of internal security checks of SharePoint, and deactivating them isn't recommended.

Therefore you abstract your main code and create a semi intelligent data binding layer in your class to load the data. Dynamically loading in the required namespace for reading in the data, by using reflection.

System.Reflection.Assembly asmbly;
asmbly = System.Reflection.Assembly.Load("Microsoft.SharePoint")

object clss;
clss = asb.CreateInstance("Microsoft.SharePoint.Foo")

Yes it would be a little more code, but if you abstract it properly and load the data into a List for example, then this code will be minimal.

Reference - Dynamic Namespace Imports and Switching:



  • If what you stated works then it's awesome !! – Muhammad Raja Apr 22 '14 at 11:16
  • I use it on a project to switch between SPO and Farm, same concept. – Hugh Wood Apr 22 '14 at 11:25
  • Ok thank you for your answer. How are developers supposed to handle this situation? Is it best practice to load the assembly with reflection? – AdelPoint Apr 23 '14 at 7:53
  • Best practice, maybe not, but if you NEED a single solution which I have needed before then it is a practice you could follow. However the best would be a single data processing library and 2 separate solutions importing that library which have the layer to get the data from the source. – Hugh Wood Apr 23 '14 at 8:26
  • Yes, that is exactly what I have. Two solutions: 1 on premise and 1 app solution and they both share the data layer. In this data layer I am trying to use the CSOM so both solutions could use it... So there is no way around your solution i guess... Thank you I will implement it the way you suggested – AdelPoint Apr 23 '14 at 9:12

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