Пустой MessageBox - C#

public void Parsing(string str)
        {
            string temp = "";
 
            for (int i = 0; i < str.Length; i++)
            {
                if (str[i] == 'u'
                    && str[i + 1] == 'p'
                    && str[i + 2] == 'd'
                    && str[i + 3] == 'a'
                    && str[i + 4] == 't'
                    && str[i + 5] == 'e'
                    && str[i + 6] == '_'
                    && str[i + 7] == 'i'
                    && str[i + 8] == 'd')
                {
                    i += 11;
                    while (str[i] < ',')
                    {
                        temp += str[i];
                        i++;
                        MessageBox.Show(temp);
                    }
                    
                    temp = "";
                }
            }
        }