private void button1_Click(object sender, EventArgs e)    {      string s = textBox1.Text;      int i = GetLength(s);      MessageBox.Show(i.ToString());    }    public static int GetLength(string str)    {      if (str.Length == 0)        return 0;      ASCIIEncoding ascii = new ASCIIEncoding();      int tempLen = 0;       byte[] s = ascii.GetBytes(str);      for (int i = 0; i < s.Length; i++)      {        if ((int)s[i] == 63)        {          tempLen += 2;        }        else        {          tempLen += 1;        }      }      return tempLen;    }

int i = System.Text.Encoding.Default.GetBytes(s).Length;