class Program
    {
        static void Main(string[] args)
        {
            //原字符串
            string str = "  hello      world,你  好 世界   !    ";
            //去掉两端空格
           str= str.Trim();
            //以空格切割
           string [] strArray= str.Split(new char[]{' '}, StringSplitOptions.RemoveEmptyEntries);
            //以空格连接
           string newStr= string.Join(" ", strArray);
            Console.WriteLine(newStr);
            Console.ReadKey();
        }
    }

class Program
    {
        static void Main(string[] args)
        {
            //原字符串
            string str = "  hello      world,你  好 世界   !    ";
            string s = Regex.Replace(str, @"\s+", " ").Trim();
            Console.WriteLine(s);
            Console.ReadKey();
        }
    }