Active Ledger Dimension 

You can use the following code sample to tet ledger dimension values for active account structure in AX 2012 & D365FO

  public static DimensionValue getdimensionValue(LedgerDimensionAccount _ledgerDimension, Name _dimensionName )

    {

        DimensionAttributeLevelValueAllView dimAttrView; //View that will display all values for ledger dimensionsDimensionAttribute dimAttr; //Main dimension attribute table

        select DisplayValue from dimAttrViewwhere dimAttrView.ValueCombinationRecId == _ledgerDimension //generalJournalAccountEntry.LedgerDimensionjoin BackingEntityType from dimAttrwhere dimAttr.RecId == dimAttrView.DimensionAttribute&& dimAttr.Name == _dimensionName; // Dimension field name

        return dimAttrView.DisplayValue;

    }