System.Globalization.TextInfo.ToTitleCase C# (CSharp) Метод

        public unsafe String ToTitleCase(String str) {
            if (str==null) 
            {
                throw new ArgumentNullException("str");
            }


            int len = str.Length;
            if (len == 0) {
                return (str);
            }

            int i;
            StringBuilder result = new StringBuilder();
            String lowercaseData = null;

            for (i = 0; i < len; i++) {
                UnicodeCategory charType;
                int charLen;

                charType = CharUnicodeInfo.InternalGetUnicodeCategory(str, i, out charLen);
                if (Char.CheckLetter(charType))
                {
                    // Do the uppercasing for the first character of the word.
                    // There are titlecase characters that need to be special treated.

                    if (charLen == 1) {
                        result.Append(nativeGetTitleCaseChar(m_pNativeTextInfo, str[i]));
                    } else {
                        //
                        // ASSUMPTION: There is no titlecase char in the surrogate.
                        //
                        char resultHighSurrogate;
                        char resultLowSurrogate;

                        ChangeCaseSurrogate(str[i], str[i+1], out resultHighSurrogate, out resultLowSurrogate, true);
                        result.Append(resultHighSurrogate);
                        result.Append(resultLowSurrogate);
                    }
                    i+= charLen;

                    //
                    // Convert the characters until the end of the this word
                    // to lowercase.
                    //
                    int lowercaseStart = i;

                    //
                    // Use hasLowerCase flag to prevent from lowercasing acronyms (like "URT", "USA", etc)
                    // This is in line with Word 2000 behavior of titilecasing.
                    //
                    bool hasLowerCase = (charType == UnicodeCategory.LowercaseLetter);
                    // Use a loop to find all of the other letters following this letter.
                    while (i < len) {
                        charType = CharUnicodeInfo.InternalGetUnicodeCategory(str, i, out charLen);
                        if (IsLetterCategory(charType)) {
                            if (charType == UnicodeCategory.LowercaseLetter) {
                                hasLowerCase = true;
                            }
                            i += charLen;
                        } else if (str[i] == '\'') {
                            // Special case for APOSTROPHE.  It should be considered part of the word.  E.g. "can't".
                            i++;
                            if (hasLowerCase) {
                                if (lowercaseData==null) {
                                    lowercaseData = this.ToLower(str);
                                }
                                result.Append(lowercaseData, lowercaseStart, i - lowercaseStart);
                            } else {
                                result.Append(str, lowercaseStart, i - lowercaseStart);
                            }
                            lowercaseStart = i;
                            hasLowerCase = true;
                        } else if (!IsWordSeparator(charType)) {
                            // This category is considered to be part of the word.
                            // This is any category that is marked as false in wordSeprator array.
                            i+= charLen;
                        } else {
                            // A word separator. Break out of the loop.
                            break;
                        }
                    }

                    int count = i - lowercaseStart;

                    if (count>0) {
                        if (hasLowerCase) {
                            if (lowercaseData==null) {
                                lowercaseData = this.ToLower(str);
                            }
                            result.Append(lowercaseData, lowercaseStart, count);
                        } else {
                            result.Append(str, lowercaseStart, count);
                        }
                    }

                    if (i < len) {
                        // Add the non-letter character.
                        if (charLen == 1) {
                            result.Append(str[i]);
                        } else {
                            // Surrogate.
                            result.Append(str[i++]);
                            result.Append(str[i]);
                        }
                    }
                } else {
                    //
                    // Not a letter, just append them.
                    //
                    if (charLen == 1) {
                        result.Append(str[i]);
                    } else {
                        // Surrogate.
                        result.Append(str[i++]);
                        result.Append(str[i]);
                    }
                }
            }
            return (result.ToString());
        }

    public string[] GetLocation(string prefixText, int count)
    {
        List <string> lst = new List <string>();

        MongoCollection <BasicInfo> objCollection = BaseClass.db.GetCollection <BasicInfo>("c_BasicInfo");
        var query = Query.Matches("HomeTown", BsonRegularExpression.Create(new System.Text.RegularExpressions.Regex("^(?i)" + prefixText + "")));

        var cursor = objCollection.Find(query);

        cursor.Limit = 5;
        System.Globalization.CultureInfo cultureInfo = System.Threading.Thread.CurrentThread.CurrentCulture;

        System.Globalization.TextInfo txtInfo = cultureInfo.TextInfo;
        foreach (var item in cursor)
        {
            lst.Add(txtInfo.ToTitleCase(item.HomeTown));
        }

        /* var query2 = Query.Matches("HomeTown", BsonRegularExpression.Create(new System.Text.RegularExpressions.Regex("^(?i)" + prefixText + "")));
         *
         * var cursor2 = objCollection.Find(query2);
         * cursor2.Limit = 5;
         * foreach (var item in cursor)
         * {
         *   lst.Add(item.HomeTown);
         *
         * }*/
        return(lst.Distinct().Take(5).ToArray());
    }