public AssociationDescription( 
   AssociationType type,
   RowHandle row1,
   RowHandle row2,
   double percentAlong
)

// Create an EditOperation
EditOperation editOperation = new EditOperation();
editOperation.Name = "Create pole; create transformer bank; attach transformer bank to pole";

// Create the transformer bank
RowToken transformerBankToken = editOperation.Create(transformerBankLayer, transformerBankAttributes);

// Create a pole
RowToken poleToken = editOperation.Create(poleLayer, poleAttributes);

// Create a structural attachment association between the pole and the transformer bank
RowHandle poleHandle = new RowHandle(poleToken);
RowHandle transformerBankHandle = new RowHandle(transformerBankToken);

AssociationDescription poleAttachment = new AssociationDescription(AssociationType.Attachment, poleHandle, transformerBankHandle);

editOperation.Create(poleAttachment);

// Execute the EditOperation
editOperation.Execute();