1   class Program
 2     {
 3         static void Main(string[] args)
 4         {
 5             //原字符串
 6             string str = "  hello      world,你  好 世界   !    ";
 7             //去掉两端空格
 8            str= str.Trim();
 9             //以空格切割
10            string [] strArray= str.Split(new char[]{' '}, StringSplitOptions.RemoveEmptyEntries);
11             //以空格连接
12            string newStr= string.Join(" ", strArray);
13             Console.WriteLine(newStr);
14             Console.ReadKey();
15         }
16     }

 1  class Program
 2     {
 3         static void Main(string[] args)
 4         {
 5             //原字符串
 6             string str = "  hello      world,你  好 世界   !    ";
 7             string s = Regex.Replace(str, @"\s+", " ").Trim();
 8             Console.WriteLine(s);
 9             Console.ReadKey();
10         }
11     }