学步园

 public void UpperFirstLetter()
        {
            //开头是一个字母或者空格后的第一个字母
            string pattern = @"\b(\w)|\s(\w)";

            string input = "i am a smart lady ";

            string output= Regex.Replace(input, pattern, match =>
            {
                return match.Value.ToUpper();
            });

            MessageBox.Show(output);

        }