Здесь я вытащил это из класса служебных строк, который у меня есть.Может быть излишним, но это полезная вещь.Используйте метод расширения ToTitleCase.
/// <summary>
/// A dictionary that holds the collection of previous title case
/// conversions so they don't have to be done again if needed more than once.
/// </summary>
private static Dictionary<string, string> _prevTitleCaseConversions = new Dictionary<String, String>();
/// <summary>
/// A collection of English words that should be lower-case in title-cased phrases.
/// </summary>
private static List<string> _englishTitleCaseLowerCaseWords = new List<string>() {"aboard", "about", "above", "across", "after",
"against", "along", "amid", "among", "anti", "around", "is", "as", "at", "before", "behind", "below",
"beneath", "beside", "besides", "between", "beyond", "but", "by", "concerning", "considering",
"despite", "down", "during", "except", "excepting", "excluding", "following", "for", "from", "in",
"inside", "into", "like", "minus", "near", "of", "off", "on", "onto", "opposite", "outside", "over",
"past", "per", "plus", "regarding", "round", "save", "since", "than", "through", "to", "toward",
"towards", "under", "underneath", "unlike", "until", "up", "upon", "versus", "via", "with", "within", "without",
"and", "but", "or", "nor", "for", "yet", "so", "although", "because", "since", "unless", "the", "a", "an"};
/// <summary>
/// Convert the provided alpha-numeric string to title case. The string may contain spaces in addition to letters and numbers, or it can be
/// one individual lowercase, uppercase, or camel case token.
/// </summary>
/// <param name="forValue">The input string which will be converted. The string can be a
/// normal string with spaces or a single token in all lowercase, all uppercase, or camel case.</param>
/// <returns>A version of the input string which has had spaces inserted between each internal "word" that is
/// delimited by an uppercase character and which has otherwise been converted to title case, i.e. all
/// words except for conjunctions, prepositions, and articles are upper case.</returns>
public static string ToTitleCase(this string forValue)
{
if (string.IsNullOrEmpty(forValue)) return forValue;
if (!Regex.IsMatch(forValue, "^[A-Za-z0-9 ]+$"))
throw new ArgumentException($@"""{forValue}"" is not a valid alpha-numeric token for this method.");
if (_prevTitleCaseConversions.ContainsKey(forValue)) return _prevTitleCaseConversions[forValue];
var tokenizedChars = GetTokenizedCharacterArray(forValue);
StringBuilder wordsSB = GetTitleCasedTokens(tokenizedChars);
string ret = wordsSB.ToString();
_prevTitleCaseConversions.Add(forValue, ret);
return ret;
}
/// <summary>
/// Convert the provided string such that first character is
/// uppercase and the remaining characters are lowercase.
/// </summary>
/// <param name="forInput">The string which will have
/// its first character converted to uppercase and
/// subsequent characters converted to lowercase.</param>
/// <returns>The provided string with its first character
/// converted to uppercase and subsequent characters converted to lowercase.</returns>
private static string FirstUpper(this string forInput)
{
return Alter(forInput, new Func<string, string>((input) => input.ToUpperInvariant()), new Func<string, string>((input) => input.ToLowerInvariant()));
}
/// <summary>
/// Return an array of characters built from the provided string with
/// spaces in between each word (token).
/// </summary>
private static ReadOnlyCollection<char> GetTokenizedCharacterArray(string fromInput)
{
var ret = new List<char>();
var tokenChars = fromInput.ToCharArray();
bool isPrevCharUpper = false;
bool isPrevPrevCharUpper = false;
bool isPrevPrevPrevCharUpper = false;
bool isNextCharUpper = false;
bool isNextCharSpace = false;
for (int i = 0; i < tokenChars.Length; i++)
{
char letter = tokenChars[i];
bool addSpace;
bool isCharUpper = char.IsUpper(letter);
if (i == 0) addSpace = false; // no space before first char.
else
{
bool isAtLastChar = i == tokenChars.Length - 1;
isNextCharUpper = !isAtLastChar && char.IsUpper(tokenChars[i + 1]);
isNextCharSpace = !isAtLastChar && !isNextCharUpper && tokenChars[i + 1].Equals(' ');
bool isInAcronym = (isCharUpper && isPrevCharUpper && (isAtLastChar || isNextCharSpace || isNextCharUpper));
addSpace = isCharUpper && !isInAcronym;
}
if (addSpace) ret.Add(' ');
ret.Add(letter);
isPrevPrevPrevCharUpper = isPrevPrevCharUpper;
isPrevPrevCharUpper = isPrevCharUpper;
isPrevCharUpper = isCharUpper;
}
return ret.AsReadOnly();
}
/// <summary>
/// Return a string builder that will produce a string which contains
/// all the tokens (words separated by spaces) in the provided collection
/// of characters and where the string conforms to title casing rules as defined above.
/// </summary>
private static StringBuilder GetTitleCasedTokens(IEnumerable<char> fromTokenChars)
{
StringBuilder wordsSB = new StringBuilder();
var comparer = StringComparer.Create(System.Globalization.CultureInfo.CurrentCulture, true);
var words = new string(fromTokenChars.ToArray()).Split(' ');
bool isFirstWord = true;
foreach (string word in words)
{
if (word.Length == 0) continue;
if (wordsSB.Length > 0) wordsSB.Append(' ');
bool isAcronym = word.Length > 1 && word.All((c) => char.IsUpper(c));
string toAppend;
// leave acronyms as-is, and lower-case all title case exceptions unless it's the first word.
if (isAcronym) toAppend = word;
else if (isFirstWord || !_englishTitleCaseLowerCaseWords.Contains(word, comparer)) toAppend = word.FirstUpper();
else toAppend = word.ToLower();
wordsSB.Append(toAppend);
isFirstWord = false;
}
return wordsSB;
}
/// <summary>
/// Convert the provided string such that first character is altered using
/// <paramref name="firstCharAlterationFunction"/> and the remaining characters
/// are altered using <paramref name="remainingCharsAlterationFunction"/>.
/// </summary>
/// <param name="forInput">The string which will have
/// its first character altered using <paramref name="firstCharAlterationFunction"/> and
/// subsequent characters altered using <paramref name="remainingCharsAlterationFunction"/>.</param>
/// <param name="firstCharAlterationFunction">The function which will
/// be used to alter the first character of the input string.</param>
/// <param name="remainingCharsAlterationFunction">The function which
/// will be used to ever character in the string after the first character.</param>
/// <returns>The provided string with its first character
/// altered using <paramref name="firstCharAlterationFunction"/> and
/// subsequent characters altered using <paramref name="remainingCharsAlterationFunction"/>.</returns>
private static string Alter(string forInput, Func<string, string> firstCharAlterationFunction, Func<string, string> remainingCharsAlterationFunction)
{
if (string.IsNullOrWhiteSpace(forInput)) return forInput;
if (forInput.Length == 1) return firstCharAlterationFunction(forInput);
return firstCharAlterationFunction(forInput[0].ToString()) + remainingCharsAlterationFunction(forInput.Substring(1));
}