using static System.Console;

using System.Globalization;

​

public class Program {

    public static void Main() {

        decimal valor;

        if (decimal.TryParse("123.45", out valor)) WriteLine(valor);

        if (decimal.TryParse("123,45", NumberStyles.AllowCurrencySymbol | NumberStyles.AllowDecimalPoint | NumberStyles.AllowThousands, new CultureInfo("pt-BR"), out valor)) {

            WriteLine(valor);

        }

    }

}