C# String Extensions

Nicify.cs

public static class StringExtensions {
    /// <summary>
    /// Transforms strings like variable and class names to nice UI-friendly strings, removing
    /// underlines, hiphens, prefixes and the like
    /// </summary>
    /// <param name="str">The string to be nicified</param>
    /// <param name="preserveAccronyms">If accronym letters should be kept together</param>
    /// <returns>A nicified Title Cased version ready for UIs</returns>
    public static string Nicify(this string str, bool preserveAccronyms = true) {
        string trimmed = str;

        if( trimmed[1] == '_' ) trimmed = trimmed.Remove(0, 2);
        if( trimmed[0] == '_' ) trimmed = trimmed.Remove(0, 1);
        if( trimmed[0].IsLowerCase() && trimmed[1].IsUpperCase() ) trimmed = trimmed.Remove(0, 1);

        string[] strs = trimmed.Split('_', '-');
        if( strs.Length == 1 ) {
            string nicified = "";
            for( int i = 0; i < trimmed.Length; i++ ) {
                if(i == 0) nicified += trimmed[i].ToUpper();
                else if(trimmed[i].IsUpperCase()) {
                    bool shouldAddSpace = !(preserveAccronyms && trimmed[i-1].IsUpperCase());
                    shouldAddSpace |= i < trimmed.Length-2 && trimmed[i+1].IsLowerCase();
                    nicified += (shouldAddSpace ? " " : "") + trimmed[i];
                } else nicified += trimmed[i];
            }

            return nicified;
        } else {
            string nicified = "";
            foreach( string s in strs ) {
                nicified += " "+s.Nicify();
            }
            return nicified.Remove(0, 1);
        }
    }

    /// <returns>Checks if a character is a lowercase letter</returns>
    public static bool IsLowerCase(this char c) {
        return (c >= 'a' && c <= 'z') || (c >= 'à' && c <= 'ý');
    }

    /// <returns>Checks if a character is an UPPERCASE letter</returns>
    public static bool IsUpperCase(this char c) {
        return (c >= 'A' && c <= 'Z') || (c >= 'À' && c <= 'Ý');
    }

    /// <returns>Checks if a character is a letter</returns>
    public static bool IsLetter(this char c) {
        return c.IsLowerCase() || c.IsUpperCase();
    }

    /// <returns>Transforms a letter to UPPERCASE</returns>
    public static char ToUpper(this char c) {
        if( c.IsLowerCase() ) return (char)(c-32);
        else return c;
    }

    /// <returns>Transforms a letter to lowercase</returns>
    public static char ToLower(this char c) {
        if( c.IsUpperCase() ) return (char)(c+32);
        else return c;
    }
}