C# (CSharp) Task4 ConnectingDB示例

示例#1

 public static ConnectingDB Instance()
 {
     if (uniqueInstance == null)
     {
         uniqueInstance = new ConnectingDB();
     }
     return(uniqueInstance);
 }

示例#2

        static void Main(string[] args)
        {
            Console.WriteLine("Hello World!");
            ConnectingDB c1      = null;
            UsingDB      usingDB = new UsingDB(c1);

            usingDB.SelectAllFromCity();
            Console.ReadKey();
        }

示例#3

 public UsingDB(ConnectingDB connectingDB)
 {
     Instance();
 }