DropdownbyKey or DropdownbyIndex?

Hi guys,

i have to implement a dropdown list. The values are items loaded from master data(backend).

With the selected item, the user will proceed something..

Question:

Should i  use a dropdownbyindex by creating a context-node (0-n) and bind the texts to the attribute.

For this solution i need to create the context node with n elements! The Lead-Selektion is set automaticly, i can read the selected element.

Or 

Should i create a dropdownbykey by creating a context-node (0-1)and set the value_set

by coding  lo_nd_node_info->set_attribute_value_set(name= ..., value_set) .

The i can read the element a the attribute value.

For this solution i need just one element!

So, which solution is more preferable? Or am i understanding something wrong?!

Thanks

Gini