[quote user="Calin Werlein"] every Datafield has one distinct ID-Number and one distinct field size[/quote]
Not sure what you mean by ID-Number. Can you post an example DGN file?
[quote user="Calin Werlein"]I need to get the datafields by field size[/quote]
Again, we need to see an example to figure out how that might work.
[quote user="Calin Werlein"]Can anyone help me with a VBA code to use as batch process?[/quote]
What knowledge of VBA do you have? Can anyone in your organisation help?