Linq To Entity 的增删改查(技术储备,怕忘了)

1.新增Customers记录
            using (NorthwindEntities myDb = new NorthwindEntities())
            {
                Customers customer = new Customers();
 
                Random rm = new Random();
 
                customer.CustomerID = "A" + rm.Next(9999).ToString();
                customer.CompanyName = "EntLib.com Forum";
                customer.Address = "http://www.EntLib.com";
 
                myDb.AddToCustomers(customer);
 
                int count = myDb.SaveChanges();
 
                txtCustomerID.Text = customer.CustomerID;
            }
 
2.更新Customers记录
            using (NorthwindEntities myDb = new NorthwindEntities())
            {
                var query = from customer in myDb.Customers
                            where customer.CustomerID == txtCustomerID.Text.Trim()
                            select customer;
 
                foreach (var row in query)
                {
                    row.CompanyName = "Updated Company Name";
                }
 
                myDb.SaveChanges();
            }
 
3.删除Customers记录
            using (NorthwindEntities myDb = new NorthwindEntities())
            {
                var query = from customer in myDb.Customers
                            where customer.CustomerID == txtCustomerID.Text.Trim()
                            select customer;
 
                foreach (var row in query)
                {
                    myDb.DeleteObject(row);
                }
 
                myDb.SaveChanges();
            }
 
4.查询Customers，返回所有记录
            using (NorthwindEntities myDb = new NorthwindEntities())
            {
                dataGridView1.DataSource = myDb.Customers;
            }