string text = "是不是漢字，ABC,柯樂(lè)義";
       for (int i = 0; i < text.Length; i++)
       {
            if ((int)text[i] > 127)
                  Console.WriteLine("是漢字");
            else
                  Console.WriteLine("不是漢字");
       }

string text = "是不是漢字，ABC,keleyi.com";
      char[] c = text.ToCharArray();

       for (int i = 0; i < c.Length;i++)
       if (c[i] >= 0x4e00 && c[i] <= 0x9fbb)
              Console.WriteLine("是漢字");
       else
              Console.WriteLine("不是漢字");

string text = "是不是漢字，ABC，keleyi.com";
        for (int i = 0; i < text.Length; i++)
        {
               if (Regex.IsMatch(text[i].ToString(), @"[/u4e00-/u9fbb]+{1}quot;))
                   Console.WriteLine("是漢字");
               else
                   Console.WriteLine("不是漢字");
        }