Linq to sql增删改查

private void button2_Click(object sender, EventArgs e)//增 { try { Customers ct = new Customers(); ct.CustomerID = "test"; ct.CompanyName = "test"; NorthwindDataContext nc = new NorthwindDataContext(); nc.Customers.InsertOnSubmit(ct); nc.SubmitChanges(); MessageBox.Show("更新成功"); } catch (Exception e1) { MessageBox.Show(e1.ToString()); } } private void button3_Click(object sender, EventArgs e)//查 { NorthwindDataContext nt = new NorthwindDataContext(); var a = from s in nt.Customers where s.CustomerID == "test" select new {s.CompanyName,s.ContactName,s.ContactTitle }; foreach (var b in a) { MessageBox.Show(b.ToString()); } } private void button4_Click(object sender, EventArgs e)//改 { try { NorthwindDataContext nw = new NorthwindDataContext(); var cityNameQuery = from cust in nw.Customers where cust.City.Contains("London") select cust; foreach (var customer in cityNameQuery) { if (customer.City == "London - Metro") { customer.City = "London"; } } nw.SubmitChanges(); MessageBox.Show("成功"); } catch (Exception e1) { MessageBox.Show(e1.ToString()); } } private void button5_Click(object sender, EventArgs e)//删 { NorthwindDataContext nw = new NorthwindDataContext(); var a = from s in nw.Customers where s.CustomerID == "jjx" select s; foreach (var b in a) { nw.Customers.DeleteOnSubmit(b); } nw.SubmitChanges(); MessageBox.Show("删除成功"); }