1、MVC EF6的增删改成小练习

namespace T4Demo{    public partial class Form1 : Form    {        NBEntities nb = new NBEntities();        public Form1()        {            InitializeComponent();        }                //新增数据        private void button1_Click(object sender, EventArgs e)        {            try            {                Sys_Log sl = new Sys_Log();                sl.F_Id = "120321023213fd0";                sl.F_Account = "super";                sl.F_NickName = "超级管理员";                sl.F_Type = "Login";                sl.F_Date = DateTime.Now;                sl.F_IPAddress = "192.168.1.1";                sl.F_IPAddressName = "江苏电信";                sl.F_ModuleName = "系统登录";                sl.F_CreatorTime = DateTime.Now;                sl.F_CreatorUserId = "101010101010";                sl.F_Result = true;                sl.F_Description = "dengluchenggong";                sl.F_CreatorUserId = "222";                sl.F_CreatorTime = DateTime.Now;                nb.Sys_Log.Add(sl); //内存上面的操作                nb.SaveChanges();            }            catch(Exception ex) { }        }        //查询        private void button2_Click(object sender, EventArgs e)        {            List
     
       ds = nb.Sys_Log.Where(p => p.F_Account == "super").ToList();            this.dataGridView1.DataSource = ds;        }        //修改数据        private void button3_Click(object sender, EventArgs e)        {            //查询要修改的数据            //(1)单行修改            //Sys_Log pEdit = nb.Sys_Log.Where(p=>p.F_Account== "super").FirstOrDefault();
     

　　　　　　　　item.F_Description = "内容被修改了";

　　　　　　　　item.F_IPAddress = "192.168.0.0";

　　　　　　　 nb.SaveChanges();

//(2)批量修改            List
     
       pEdit = nb.Sys_Log.Where(p=>p.F_Account=="super").ToList();            //保存修改            foreach (Sys_Log item in pEdit)            {                item.F_Description = "内容被修改了";                item.F_IPAddress = "192.168.0.0";            }            nb.SaveChanges();        }        //删除数据        private void button4_Click(object sender, EventArgs e)        {            //(1)先查后删 根据ID删除            Sys_Log sl = nb.Sys_Log.Where(p => p.F_Id == "1203210232100").FirstOrDefault();            nb.Sys_Log.Remove(sl);            nb.SaveChanges(); //(2)自己手动添加            Sys_Log sls = new Sys_Log() { F_Id= "120321023213fd0" };            //附件到实体上下文            nb.Sys_Log.Attach(sls);            nb.Sys_Log.Remove(sls);            nb.SaveChanges();        }    }}