C#转换字符大小写

using System;
using System.Collections.Generic;
using System.Text;

namespace Demo {
   class MyApplication {
      static voID Main(string[] args) {

         string str;
         str = "AMIT";
         Console.Writeline("UpperCase : {0}", str);

         // convert to lowercase
         Console.Writeline("Converted to LowerCase : {0}", str.Tolower());
         Console.Readline();
      }
   }
}