In this article I am explaining the step by step procedure to create a sandbox solution with full trust proxy.

Before starting I am assuming you are aware of the sandbox limitations. Full trust solution is providing sandbox solution to work in a full environment. In short this is the way to achieve farm based solution functionality in a Sandbox.

Namespace Required:

using Microsoft.SharePoint.UserCode;
using Microsoft.SharePoint.Security;
using System.Security.Permissions;
using Microsoft.SharePoint;
using Microsoft.SharePoint.Publishing;

Step 1: Create a simple sharepoint solution with Sandbox; choose create webpart:

FTProxy1.gif

Step 2: In the webpart, add the logic for creating the web part:

FTProxy2.gif

Step 3: Deploy the webpart and see the UI:

FTProxy3.gif

Step 4: Create a new project under the same solution; give it a name and Click Ok:

FTProxy4.gif

Step 5: Create two classes under full trust class library. One for ProxyArg and the other for ProxyOperation.

FTProxy5.gif

Step 6: Add the reference to the Fulltrust code in webpart like below:

string st= SPUtility.ExecuteRegisteredProxyOperation(assemblyName,typeName, new ProxyArg(URL, txtEnter.Text)).ToString();

Step 7: Add the code logic and deploy the solution. Put the solution GAC and take the reference in Webpart solution.

Step 8: Use the attached powershell script for registering the full trust code in sandbox solution. Deploy the webpart.

It will look like below
:
FTProxy6.gif

And you can check the page library also:

FTProxy7.gif

That's it. We are done with our solution. Hope you like this article.