如何摆脱日文字符?

public static string EscapeString(string s)
{
    StringBuilder sb = new StringBuilder();

    foreach (char c in s)
    {
                int i = (int)c;
                if (i < 32 || i > 126)
                {
                    sb.AppendFormat("&#{0};", i);
                }
                else
                {
                    sb.Append(c);
                }

    }

    return sb.ToString();
}