糊涂问题

在写ras拨号的时把256写错为20，这个糊涂问题居然花了我半天时间，

        const int RAS_MaxEntryName = 256;
        const int RAS_MaxPhoneNumber = 128;
        const int RAS_MaxCallbackNumber = 128;
        const int UNLEN = 256;
        const int PWLEN = 256;
        const int DNLEN = 15;
        
        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
        public struct RASDIALPARAMS
        {
            public int dwSize;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = RAS_MaxEntryName + 1)]
            public string szEntryName;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = RAS_MaxPhoneNumber + 1)]
            public string szPhoneNumber;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = RAS_MaxCallbackNumber + 1)]
            public string szCallbackNumber;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = UNLEN + 1)]
            public string szUserName;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = PWLEN + 1)]
            public string szPassword;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = DNLEN + 1)]
            public string szDomain;
            public int dwSubEntry;
            public int dwCallbackId;
        }