System.Xml.XmlComplianceUtil.IsValidLanguageID C# (CSharp) Méthode

        public static bool IsValidLanguageID( char[] value, int startPos, int length ) {
            int len = length;
            if ( len < 2 ) {
                return false;
            }

            bool fSeenLetter = false;
            int i = startPos;
            XmlCharType xmlCharType = XmlCharType.Instance;

            char ch = value[i];
            if ( xmlCharType.IsLetter(ch) ) {
                if ( xmlCharType.IsLetter( value[++i] ) ) {
                    if ( len == 2 ) {
                        return true;
                    }
                    len--;
                    i++;
                }
                else if ( ('I' != ch && 'i' != ch ) && ( 'X' != ch && 'x' != ch ) ) {  //IANA or custom Code
                    return false;
                }

                if ( value[i] != '-' ) {
                    return false;
                }

                len -= 2;
                while ( len-- > 0 ) {
                    ch = value[++i];
                    if ( xmlCharType.IsLetter( ch ) ) {
                        fSeenLetter = true;
                    }
                    else if ( ch == '-' && fSeenLetter ) {
                        fSeenLetter = false;
                    }
                    else {
                        return false;
                    }
                }
                if ( fSeenLetter ) {
                    return true;
                }
            }
            return false;
        }
    }