ToTitleCaseFromPascal

ToTitleFromPascalCase

static string ToTitleFromPascalCase(string s) {
    var sb = new StringBuilder();

    for (var i = 0; i < s.Length; i++) {
        var c = s[i];

        if (c == ' ') { continue; }
        if (i == 0) { sb.Append(c); continue; }
        if (!char.IsUpper(c)) { sb.Append(c); continue; }
        if (!char.IsUpper(s[i - 1])) { sb.Append(' ').Append(c); continue; }

        var ii = i + 1;
        if (ii < s.Length && !char.IsUpper(s[ii])) { sb.Append(' ').Append(c); continue; }

        sb.Append(c);
    }

    return sb.ToString();
}