Try something like this:
<%# Math.Round(double.Parse(Replace(Eval("VPC"), ".", ",")) / 7.5345, 2, MidpointRounding.ToEven).ToString("0.00") & If(CDate(Eval("DATUM")) <= CDate("2022-12-31"), " Kn", " €") %>
Probably some adjustments are needed according to other details.