Sample code (C#) for Multi-Table Lookup / Polymorphic Lookup attribute in Dataverse / Dynamics 365

string ConnectionString = "AuthType = OAuth; " + "AppId=51f81489-12ee-4a9e-aaae-a2591f45987d; " + "Username=user@domain.onmicrosoft.com; " + "Password=pwd; " + "RedirectUri=app://58145B91-0C36-4500-8554-080854F2AC97;" + "Url = https://orgname.crm4.dynamics.com/;"; CrmServiceClient svc = new CrmServiceClient(ConnectionString); if (svc.IsReady) { // Create PolymorphicLookupAttribute // with mycustomtable custom entity / table // referencing case, contact and account entity var varOrgRequest = new OrganizationRequest(); // specify the request name varOrgRequest.RequestName = "CreatePolymorphicLookupAttribute"; // specify lookup attribute details varOrgRequest.Parameters["Lookup"] = new LookupAttributeMetadata() { SchemaName = "crf82_mypolymorphiclookup", DisplayName = new Label("My Polymorphic Lookup", 1033) }; // referencing entity is our custom entity named my custom table // referenced entity is incident var oneToManyRelation1 = new OneToManyRelationshipMetadata(); oneToManyRelation1.ReferencingEntity = "crf82_mycustomtable"; oneToManyRelation1.ReferencedEntity = "incident"; oneToManyRelation1.SchemaName = "crf82_mycustomtable_crf82_incident"; // referencing entity is our custom entity named my custom table // referenced entity is contact var oneToManyRelation2 = new OneToManyRelationshipMetadata(); oneToManyRelation2.ReferencingEntity = "crf82_mycustomtable"; oneToManyRelation2.ReferencedEntity = "contact"; oneToManyRelation2.SchemaName = "crf82_mycustomtable_crf82_contact"; // referencing entity is our custom entity named my custom table // referenced entity is account var oneToManyRelation3 = new OneToManyRelationshipMetadata(); oneToManyRelation3.ReferencingEntity = "crf82_mycustomtable"; oneToManyRelation3.ReferencedEntity = "account"; oneToManyRelation3.SchemaName = "crf82_mycustomtable_crf82_account"; // populate OneToManyRelationships parameter of CreatePolymorphicLookupAttribute request varOrgRequest.Parameters["OneToManyRelationships"] = new OneToManyRelationshipMetadata[] { oneToManyRelation1, oneToManyRelation2, oneToManyRelation3 }; // specify the existing solution name varOrgRequest.Parameters["SolutionUniqueName"] = "MySolution"; var response = svc.Execute(varOrgRequest); }

 var createOneToManyRelationshipRequest = new CreateOneToManyRequest(); // referencing entity is our custom entity named mycustomtable // referenced entity is contact - add the entity to be added var oneToManyRelationAdd = new OneToManyRelationshipMetadata(); oneToManyRelationAdd.ReferencingEntity = "crf82_mycustomtable"; oneToManyRelationAdd.ReferencedEntity = "contact"; oneToManyRelationAdd.SchemaName = "crf82_mycustomtable_crf82_contact"; createOneToManyRelationshipRequest.OneToManyRelationship = oneToManyRelationAdd; // specify lookup attribute details to which new relationship is to be added createOneToManyRelationshipRequest.Parameters["Lookup"] = new LookupAttributeMetadata() { SchemaName = "crf82_mypolymorphiclookup", DisplayName = new Label("My Polymorphic Lookup", 1033) }; var createOneToManyRelationshipResponse = svc.Execute(createOneToManyRelationshipRequest);

 var deleteRelationShip = new DeleteRelationshipRequest(); // specify schema name of the relationship deleteRelationShip.Name = "crf82_mycustomtable_crf82_contact1"; svc.Execute(deleteRelationShip);

 // User delete attribute request DeleteAttributeRequest varDelRequest = new DeleteAttributeRequest(); // specify the entity name varDelRequest.EntityLogicalName = "crf82_mycustomtable"; // specify the schema name of the entity varDelRequest.LogicalName = "crf82_mymultitablelookup"; svc.Execute(varDelRequest);