Associate the Security Roles to System User

Below piece of C# code associate the Security Roles to specified System User in Microsoft Dynamics CRM 2011.

using Microsoft.Crm.Sdk.Messages;

EntityReference Monikar1 = new EntityReference();

Monikar1.Id = id;

Monikar1.Name = "systemuser";

AssociateEntitiesRequest associatedRequest = new AssociateEntitiesRequest();

associatedRequest.Moniker1 = new EntityReference { 

    Id = Monikar1.Id, LogicalName = Monikar1.Name 

};

associatedRequest.RelationshipName = "systemuserroles_association";

foreach (var role in securityRoles)

{

    EntityReference Moniker2 = null;

    Moniker2 = new EntityReference();

    Moniker2.Name = "role";

    Moniker2.LogicalName = "role";

    Moniker2.Id = new Guid(role.Id.ToString());

    associatedRequest.Moniker2 = new EntityReference { 

        Id = Moniker2.Id, LogicalName = Moniker2.LogicalName

    };

    service.Execute(associatedRequest);

}