One of the limitation, that we have on MS Dynamics CRM Online(CRM 4.0) is that it does not support plug-ins. In CRM 4.0 one has to register the plugins on the CRM Server to extend the CRM capabilities which is possible for the On-Premise setups. CRM 2011 has addressed this issue by introducing the sandbox isolation mode while registering the plugins. As a result of this, now one can extend the functionality of CRM Online 2011 through the plugins.In other words, Microsoft Dynamics CRM Online 2011 support the execution of plug-ins in an isolated environment.
Please make a note that with the sandbox mode, followings things donot work
1.Accessing the webservice using localhost or ipaddress.
2.CRM LINQ Queries
3.Default Credentials while accessing a webservice.
4.Access to the file system, registry, system event log, network is prevented.
Debuging the Plugin:
It is important for a developers to debug the plugin. In CRM4, the plugin needs to be stored on the disk i.e. inside Server\Bin\Assembly folder to make the debugger work. But now with the sandbox mode, the plugin can be debugged even it is stored in the database. The steps for debugging a sandbox plugin are as follows.
1. On the sandbox server,set the following registry key to 1 .
2.Copy the pdb file of the plugin assembly to the sandbox server’s server/bin/assembly folder
3.Attach the debugger to all of the “Microsoft.Crm.Sandbox.WorkerProcess.exe” processes in Visual Studio.