How to get Request Offering from given Service Offering using Service Manager SDK?

Question

Recently, I am working on application where I have to fetch all Request Offering from given Service Offering. 
I can retrieve all Request Offering using following method of SM SDK : 
var requestOfferings = group.Extensions.Retrieve<RequestOffering>();// group is Management Group
But I am unable to get request Offering from given Service Offering as I am new to this platform. I have searched in web but can not find solution to this problem.
It would be great if someone guide for this problem or give me any suggestion related to this problem.
Thanks in advance.

Answer 1

RequestOfferings are handled a little differently in the SDK, but fortunately, they're still backed by standard EnterpriseManagementObjects..it just takes a little work to get them.
There are a few ways you can go about getting a request offering's related service offerings. I'm going to show you the relationship route, but you could also use a type projection to achieve the same goal.
In your original post, you're simply retrieving _all_ request offerings..that's fine. If you wanted to retrieve a single request offering (as I do in my example) you need to find the request offering's identifier. This identifier is a pipe delimited string
of various values. The quickest way to find it, in my opinion, is to query the MT_System$RequestOffering table in the database, but you can also find it by looping through all the RequestOfferings returned by group.Extensions.Retrieve<RequestOffering>();
Anyway, for the following example to work, you only need your request offering's Identifier and your management server name. (Again, you could simply loop through all of your request offerings and retrieve the service offerings for all of them)
The comments inline with this example should guide you through the steps.
//Connect to the management group and prepare the class and relationship types that we'll need.
String strMySCSMServer = "your server";
EnterpriseManagementGroup emg = new EnterpriseManagementGroup(strMySCSMServer);
ManagementPackClass mpcRO = emg.EntityTypes.GetClass(new Guid("8FC1CD4A-B39E-2879-2BA8-B7036F9D8EE7")); //System.RequestOffering
ManagementPackRelationship relSORelatesToRO = emg.EntityTypes.GetRelationshipClass(new Guid("BE417A55-6622-0FC3-FCEA-90CD23E0FC23")); //System.ServiceOfferingRelatesToRequestOffering
//An example of an extension identifier looks like this:
//1|My.RO.MP|1.0.0.0|Offeringc921c4feujhoi8cdsjloiz352d7gf3k0|3|RequestOffering
String strRequestOfferingIdentifier = "your request offering identifier";
//Retrieve the request offering using an Extension Identifier.
ExtensionIdentifier ei = null;
ExtensionIdentifier.TryParse(strRequestOfferingIdentifier, out ei);
RequestOffering ro = emg.Extensions.Retrieve<RequestOffering>(ei);
//Using the request offering's Identifier, retrieve the enterprise management object that it represents
EnterpriseManagementObjectCriteria emocRO = new EnterpriseManagementObjectCriteria("ID = '" + ro.Identifier + "'", mpcRO);
IObjectReader<EnterpriseManagementObject> orROs = emg.EntityObjects.GetObjectReader<EnterpriseManagementObject>(emocRO, ObjectQueryOptions.Default);
//Since we queried for only a single Request Offering, the object reader should contain 0 or 1 elements.
EnterpriseManagementObject emoRO = null;
if (orROs.Count > 0)
emoRO = orROs.ElementAt(0);
else
Console.WriteLine("No Request Offering found");
//Now, using the relationship type "System.ServiceOfferingRelatesToRequestOffering", get all Service Offering's related to our request offering
IList<EnterpriseManagementRelationshipObject<EnterpriseManagementObject>> lstEMROs = emg.EntityObjects.GetRelationshipObjectsWhereTarget<EnterpriseManagementObject>(emoRO.Id, relSORelatesToRO, DerivedClassTraversalDepth.None, TraversalDepth.OneLevel, ObjectQueryOptions.Default);
//The GetRelationshipObjectsWhereTarget method returns a list of EnterpriseManagementObjectRelationships..These objects represent that relationship between two objects.
//Thus, these relationship objects have two properties of interest; TargetObject and SourceObject. In this case, service offerings are the source of this relationship type and
//so, you can access the service offering object itself by using the relationship object's SourceObject property (which is nothing more than an EnterpriseManagementObject)
foreach (EnterpriseManagementRelationshipObject<EnterpriseManagementObject> emro in lstEMROs)
//emro.SourceObject is your Service Offering object. You can use it for whatever you need from here on out. In this example, i'm just writing out the DisplayName
EnterpriseManagementObject emoServiceOffering = emro.SourceObject;
Console.WriteLine(emoServiceOffering[null, "DisplayName"].Value);
Give it a try, let me know if you have any questions :)