Using code128 with font ttf.

Hello. I am developing a system in Windows Form, where there will be a report and a field will be a barcode. The problem is that when I pass the numeral 123456789 through the bar code parameter, it is created, but I can't read the code at all. I read on various forums how to do the calculation. But I can't implement it at all.
Where am I going wrong?

public string ReturnCode128(string text)
        {
            const int codetype = 105;
            string textcode = text.Trim();
            int quantidade = textcode.Length;
            int[] arrayintcode = new int[quantidade];

            for(int i = 0; i < quantidade; i++)
            {
                char valToConvertToASCII = Convert.ToChar(textcode[i]);
                int valToMultiply = valToConvertToASCII- 32;
                arrayintcode[i] = valToMultiply;
            }

            string[] codemulti = new string[quantidade + 3];
            codemulti[0] = codetype.ToString();
            for(int i = 1; i < quantidade+1; i++)
            {
                codemulti[i] = (i*arrayintcode[i-1]).ToString();
            }

            int value = 0;
            for(int i = 0; i < codemulti.Count(); i++)
            {
                value += Convert.ToInt32(codemulti[i]);
            }

            int module = value % codetype;

            char charverify = (char)(module + 32);

            char start = (char)186;
            char stop = (char)186;

            return $"{start}{textcode}{charverify}{stop}";
        }