How to get right dimension?

I have one Big assembly, where have one part with two different configurations (A and B).

When I use macro to get dimension (for example width of detail):

Dimension swDim = swModel.Parameter("D1@Sketch@part1.Part");

string myValue = swDim.Value.ToString();

So I have value 100 or 200, and it depends on which configuration was opened or edited last.

How to know right dimension(for example, if I want to know width of configuration A)???