求一个简单的c# .net源码

我也是刚学的，希望这些东西对你有用

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

using System.Data;
using System.Data.SqlClient;

namespace AdoDotNetDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            QueryDemo();
            //DataUpdateDemo();
        }

        /// <summary>
        /// 演示使用执行数据的插入、更新、删除
        /// </summary>
        private static void DataUpdateDemo()
        {
            string strConnectionString = @"Data Source=(local)\SQLExpress;Initial Catalog=demo_1;Integrated Security=SSPI;";

            //创建并打开数据库联接
            SqlConnection conn = new SqlConnection(strConnectionString);
            conn.Open();


            //利用SqlCommand对象执行insert语句插入数据

            string strInsert = "insert into TB_STUDENTS (STU_KEY,STU_ID,STU_NAME,STU_GENDER,STU_BIRTHDATE,CLS_ID) values ("
                + "'c805909e-3aac-43e3-9cef-d205c494015c','20090917','李隆基','男','1989-02-17','1d5de51e-0720-49fa-9059-c48eca68b4dd')";

            SqlCommand cmd = new SqlCommand(strInsert, conn);   //可以在SqlCommand的构造方法里面传入SQL语句作为参数


            int insertedCount = cmd.ExecuteNonQuery();  //调用ExecutedNonQuery方法执行insert/update/delete语句完成数据的插入/修改/删除

            Console.WriteLine("{0}行数据被插入。", insertedCount);

            Console.ReadLine();

            //利用SqlCommand对象执行update语句更新数据表中的数据
            string strUpdate = "update TB_STUDENTS set STU_NAME='朱棣' where STU_KEY='d0c5130a-05c2-435f-9ba3-a35463a7d98a'";

             = strUpdate;        //修改cmd对象的SQL语句，由刚才的insert变成了update，可以通过CommandText属性为SqlCommand对象指定要执行的SQL语句

            int updatedCount = cmd.ExecuteNonQuery();

            Console.WriteLine("{0}行数据被修改。", updatedCount);

            Console.ReadLine();


            //利用SqlCommand对象执行delete语句删除记录
            string strDelete = "delete from TB_STUDENTS where STU_KEY='c805909e-3aac-43e3-9cef-d205c494015c'";

             = strDelete;

            int deletedCount = cmd.ExecuteNonQuery();

            Console.WriteLine("{0}行数据被删除。", deletedCount);

            conn.Close();

            Console.ReadLine();


        }

        /// <summary>
        /// 演示使用执行select语句进行数据查询
        /// </summary>
        private static void QueryDemo()
        {
            //创建数据库联接字符串
            //Data Source=(local)\SQLExpress;   用来指定要访问的SQLServer服务实例，这里是本机的SQLExpress实例
            //Initial Catalog=demo_1;   指定要访问的数据库，这里的数据库是demo_1；
            //Integrated Security=SSPI; 指定访问SQLServer时使用Windows集成身份验证;
            //如果想使用SQLServer身份验证，可以用 uid=用户名;pwd=口令;指定用户名和口令
            string strConnectionString = @"Data Source=(local)\SQLExpress;Initial Catalog=demo_1;Integrated Security=SSPI;";

            //创建并打开数据库联接
            SqlConnection conn = new SqlConnection(strConnectionString);
            conn.Open();


            //利用SqlCommand对象执行Select语句
            string strSelect = "select * from TB_STUDENTS";
            SqlCommand cmd = new SqlCommand(strSelect, conn);


            SqlDataReader dataReader = cmd.ExecuteReader();     //dataReader就是Select语句返回的结果集


            //循环取出dataReader中的每一条记录，如果Read方法返回true,说明成功指向下一条记录，否则
            //表示已经到了结果集尾部，结束循环
            while (dataReader.Read())
            {
                Guid stuKey = (Guid)dataReader["STU_KEY"];  //取出STU_KEY字段的值，SQLServer中的uniqueidentifier类型对应于C#中的Guid类型
                string stuId = (string)dataReader["STU_ID"];    //SQLServer中的varchar类型对应于C#中的string类型
                string stuName = (string)dataReader["STU_NAME"];    //SQLServer中的nvarchar类型对应于C#中的string类型
                string stuGender = (string)dataReader["STU_GENDER"];

                DateTime stuBirthDate = (DateTime)dataReader["STU_BIRTHDATE"];  //datetime -> DateTime

                Guid clsId = (Guid)dataReader["CLS_ID"];


                Console.WriteLine("学生代码{0},学号{1},姓名{2},性别{3},出生日期{4},班级代码{5}",
                    stuKey, stuId, stuName, stuGender, stuBirthDate, clsId);

            }

            dataReader.Close();     //关闭dataReader，释放资源
            conn.Close();           //关闭Connection，释放资源

        }
    }
}