Retrieve System Users by a Security Role (CRM 2011)

We have had the need to retrieve an entity collection of system users from a security role in a plugin. We developed a method that accept the role's name and a collection of attributes of System User entity.
In this method we use query expression to retrieve the system user specifying a link to entity "SystemUserRoles" and then a link to the "Role" entity. The linking attribute is the SystemUserId for the first link and the RoleId for the second one.
Finally a condition on the role's name to filter the system users.

public EntityCollection RetrieveUsersInfoByRole(string roleName,
                                                string[] userColumnSet)

{

    try

    {

        serviceProxy = ServiceConnector.

                       GetOrganizationService("<Organization.svc URL>");

 

        QueryExpression query = new QueryExpression("systemuser");

        query.ColumnSet = new ColumnSet(userColumnSet);

        query.Distinct = true;

        query.Criteria = new FilterExpression();

        //Add link to system user roles and role

        query.AddLink("systemuserroles", "systemuserid", "systemuserid").

            AddLink("role", "roleid", "roleid").LinkCriteria.

            AddCondition("name", ConditionOperator.Equal, roleName);

 

        EntityCollection users = serviceProxy.RetrieveMultiple(query);

 

        return users;

    }

    catch (Exception ex)

    {

        throw ex;

    }

}

 

Hope it can be useful.

Happy CRM coding