How to get the Contact Guids from a PartyList in a Plugin?

Question

I'm making a plugin that triggers on the create message of a custom activity SMS. These plugin will send the actual sms using a third party sms service provider.

Therefore i need to get the mobilephone numbers for every contact in the "To" field of the SMS activity. This is a field of type: PartyList.

I'm currently using the following code:

EntityCollection Recipients;
Entity entity = (Entity) context.InputParameters["Target"];

IOrganizationServiceFactory serviceFactory = (IOrganizationServiceFactory)serviceProvider.GetService(typeof(IOrganizationServiceFactory));
IOrganizationService service = serviceFactory.CreateOrganizationService(context.UserId);

Content = entity.GetAttributeValue<String>("subject");
Recipients = entity.GetAttributeValue<EntityCollection>("to");

for (int i = 0; i < Recipients.Entities.Count; i++)
{
  Entity ent= Recipients[i];

  string number = ent["MobilePhone"].ToString();    
}

But this is not working, i think the ent variable contains no attributes.

I've tried coding with ActivityParty also but not luck either.

I hope someone of you can help me with this one.

Thanks!

Answer 1

Here's is how I finally did it:

EntityCollection Recipients;
Entity entity = (Entity) context.InputParameters["Target"];

IOrganizationServiceFactory serviceFactory 
  = (IOrganizationServiceFactory)serviceProvider.GetService(
    typeof(IOrganizationServiceFactory)); 
IOrganizationService service = serviceFactory
  .CreateOrganizationService(context.UserId); 

Content = entity.GetAttributeValue<String>("subject"); 
Recipients = entity.GetAttributeValue<EntityCollection>("to"); 

for (int i = 0; i < Recipients.Entities.Count; i++)
{
  ActivityParty ap = Recipients[i].ToEntity<ActivityParty>();
  String contactid = ap.PartyId.Id.ToString();
  Contact c = (Contact) service.Retrieve(
    Contact.EntityLogicalName,
    ap.PartyId.Id,
    new ColumnSet(new string[]{ "mobilephone" }));
  String mobilephone = c.MobilePhone;
  ...
}