单件模式 SinglePattern

using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Data.SqlClient;

namespace SinglePattern
{
    class ConnectionItem
    {
        private SqlConnection conn;
        private string _Name;
        public ConnectionItem() {
            conn = new SqlConnection("Server=localhost//GhostBear ;Initial Catalog=MAMA;UID=sa;PWD=shayidao9788;");
            conn.Open();
            _Name = new Random().Next(1, 100).ToString();
        }
        public string State
        {
            get {
               
                    return conn.State.ToString();

            
            }
        }
        public void Close()
        {
            conn.Close();

        }
        public void Open()
        {
            if (conn.State != ConnectionState.Open)
                conn.Open();
        }
        public SqlConnection Connection
        {
            get { return conn; }
        }
        public string Name
        {
            get { return _Name; }
        }

    }
}

单件对象

using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Data.SqlClient;
using System.Collections;


namespace SinglePattern
{
    class ConnectionPool
    {
        private static ConnectionItem _Connection=null;
        private ConnectionPool()
        {
            _Connection = new ConnectionItem();
            _Connection.Open();
           
        }
        public static ConnectionItem GetConnection()
        {
            if (_Connection == null)
                new ConnectionPool();
           
             return _Connection;
        }


    }
}

单件对象所需的组合类

using System;
using System.Collections.Generic;
using System.Text;
using System.Data.SqlClient;

namespace SinglePattern
{
    class Program
    {
        static void Main(string[] args)
        {
            ConnectionItem ci;
            ci = ConnectionPool.GetConnection();
            SqlCommand cmd1=new SqlCommand("insert into Commodity values('a',1,'a',1,'6e81540d-6604-4378-b731-29280f839cd9')");
            SqlCommand cmd2 = new SqlCommand("insert into Commodity values('b',1,'b',1,'6e81540d-6604-4378-b731-29280f839cd9')");
            SqlCommand cmd3 = new SqlCommand("insert into Commodity values('c',1,'c',1,'6e81540d-6604-4378-b731-29280f839cd9')");
            SqlCommand cmd4 = new SqlCommand("insert into Commodity values('d',1,'d',1,'6e81540d-6604-4378-b731-29280f839cd9')");
            SqlCommand cmd5 = new SqlCommand("insert into Commodity values('e',1,'e',1,'6e81540d-6604-4378-b731-29280f839cd9')");
            cmd1.Connection = ci.Connection;
            cmd2.Connection = ci.Connection;
            cmd3.Connection = ci.Connection;
            cmd4.Connection = ci.Connection;
            cmd5.Connection = ci.Connection;
            cmd1.ExecuteNonQuery();
            cmd2.ExecuteNonQuery();
            cmd3.ExecuteNonQuery();
            cmd4.ExecuteNonQuery();
            cmd5.ExecuteNonQuery();
            ci.Close();
            Console.ReadLine();

        }
    }
}

代码调用者