ADO.NET连接SQLServer数据库

引入ADO.NET组件命名空间 引入SQL数据提供程序(包括SQL版本的核心对象)

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创建SQL版本连接实例核心对象,用于连接数据源

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将数据源连接必要信息以字符串形式赋给ConectionString属性

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State属性用于查看当前连接的状态

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打开当前数据库

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关闭当前数据库

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控制台查看

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State_Change事件在连接状态改变时触发

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代码

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Data;              //引入ADO.NET组件命名空间using System.Data.SqlClient;    //引入SQL数据提供程序(包括SQL版本的核心对象)namespace ADO.NETyouping{    class Program    {        static void Main(string[] args)        {            //测试数据库连接            TestingConnection();        }        //测试数据库连接        private static void TestingConnection()        {            //创建SQL版本连接实例核心对象,用于连接数据源            SqlConnection conn = new SqlConnection();            //将数据源连接必要信息以字符串形式赋给ConectionString属性            conn.ConnectionString = @"Server=.;DataBase=StudentManageDB;Uid=sa;Pwd=aaa999a9";            //State属性用于查看当前连接的状态            Console.WriteLine(conn.State);            //打开当前数据库            conn.Open();            Console.WriteLine(conn.State);            //关闭当前数据库            conn.Close();            Console.WriteLine(conn.State);        }    }}

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## 连接测试(带有try….catch) ##

代码：

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Data;              //引入ADO.NET组件命名空间using System.Data.SqlClient;    //引入SQL数据提供程序(包括SQL版本的核心对象)namespace ADO.NETyouping{    class Program    {        static void Main(string[] args)        {            //测试数据库连接                      TestingConnectionWithTryCatch();        }        //连接测试(带有try....catch)        private static void TestingConnectionWithTryCatch()        {            SqlConnection conn = new SqlConnection();            conn.ConnectionString = @"Server=.;DataBase=StudentManage;Uid=sa;Pwd=aaa999a98;";            try            {                conn.Open();                Console.WriteLine("链接状态：{0}",conn.State);            }            catch (SqlException ex)            {                Console.WriteLine("数据库链接打开遇到异常！");                Console.WriteLine(ex.Message);                throw;            }            finally            {                if(conn.State != ConnectionState.Closed)                {                    conn.Close();                }            }        }

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使用using确保链接资源释放

代码

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Data;              //引入ADO.NET组件命名空间using System.Data.SqlClient;    //引入SQL数据提供程序(包括SQL版本的核心对象)namespace ADO.NETyouping{    class Program    {        static void Main(string[] args)        {            //测试数据库连接            //TestingConnection();            // TestingConnectionWithTryCatch();            TestingConnetionWithUsing();        }        //使用using确保链接资源释放        private static void TestingConnetionWithUsing()        {            using (SqlConnection conn = new SqlConnection())            {                conn.ConnectionString = @"Server=.;DataBase=StudentManageDB;";                    conn.ConnectionString +=@"Uid=sa;Pwd=aaa999a9";                conn.Open();                Console.WriteLine(conn.State);            }        }

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全部代码：

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Data;              //引入ADO.NET组件命名空间using System.Data.SqlClient;    //引入SQL数据提供程序(包括SQL版本的核心对象)namespace ADO.NETyouping{    class Program    {        static void Main(string[] args)        {            //测试数据库连接            //TestingConnection();            // TestingConnectionWithTryCatch();            TestingConnetionWithUsing();        }        //使用using确保链接资源释放        private static void TestingConnetionWithUsing()        {            using (SqlConnection conn = new SqlConnection())            {                conn.ConnectionString = @"Server=.;DataBase=StudentManageDB;";                    conn.ConnectionString +=@"Uid=sa;Pwd=aaa999a9";                conn.Open();                Console.WriteLine(conn.State);            }        }        //连接测试(带有try....catch)        private static void TestingConnectionWithTryCatch()        {            SqlConnection conn = new SqlConnection();            conn.ConnectionString = @"Server=.;DataBase=StudentManage;Uid=sa;Pwd=aaa999a98;";            try            {                conn.Open();                Console.WriteLine("链接状态：{0}",conn.State);            }            catch (SqlException ex)            {                Console.WriteLine("数据库链接打开遇到异常！");                Console.WriteLine(ex.Message);                throw;            }            finally            {                if(conn.State != ConnectionState.Closed)                {                    conn.Close();                }            }        }        //测试数据库连接        private static void TestingConnection()        {            //创建SQL版本连接实例核心对象,用于连接数据源            SqlConnection conn = new SqlConnection();            //将数据源连接必要信息以字符串形式赋给ConectionString属性            conn.ConnectionString = @"Server=.;DataBase=StudentManageDB;Uid=sa;Pwd=aaa999a9";            //State属性用于查看当前连接的状态            //Console.WriteLine(conn.State);            //State_Change事件在连接状态改变时触发            conn.StateChange += Conn_StateChange;            //打开当前数据库            conn.Open();            //Console.WriteLine(conn.State);            //关闭当前数据库            conn.Close();            //Console.WriteLine(conn.State);        }        private static void Conn_StateChange(object sender, StateChangeEventArgs e)        {            Console.WriteLine("当前连接状态:{0}",e.CurrentState.ToString());        }    }}