public static extern Int32 TwGetParamStr( [In] IntPtr bar, [In, MarshalAs(UnmanagedType.LPStr)] String varName, [In, MarshalAs(UnmanagedType.LPStr)] String paramName, [In] Tw.ParamValueType type, [In] uint maxStrLength, [Out, MarshalAs(UnmanagedType.LPStr)] StringBuilder param);