// Create edit operation
EditOperation editOperation = new EditOperation();
editOperation.Name = "Create structural attachment association";
// Create a RowHandle for the pole
Element poleElement = utilityNetwork.CreateElement(poleAssetType, poleGlobalID);
RowHandle poleRowHandle = new RowHandle(poleElement, utilityNetwork);
// Create a RowHandle for the transformer bank
Element transformerBankElement = utilityNetwork.CreateElement(transformerBankAssetType, transformerBankGlobalID);
RowHandle transformerBankRowHandle = new RowHandle(transformerBankElement, utilityNetwork);
// Attach the transformer bank to the pole
AssociationDescription structuralAttachmentAssociationDescription = new AssociationDescription(AssociationType.Attachment, poleRowHandle, transformerBankRowHandle);
editOperation.Create(structuralAttachmentAssociationDescription);
editOperation.Execute();