protected void Button1_Click(object sender, EventArgs e)
{
yyEntities _db;
_db = new yyEntities();
test t = new test();
t.testName = this.TextBox1.Text;
t.testCon = this.TextBox2.Text;
_db.AddObject("test", t);
_db.SaveChanges();
//using (var edm = new yyEntities())
//{
// test c = new test { testName = "c2", testCon = "成都市2" };
// edm.AddObject("test", c);
// int result = edm.SaveChanges();
//}
}
其中，在代码中，需要注意的是：AddObject方法中参数“entitySetName ”就是指对应实体名称，应该是：“Customers”，而不是“NorthwindEntities.Customers”；
l 更新：
using (var edm = new NorthwindEntities())
{
Customers addc = edm.Customers.FirstOrDefault(cc => cc.CustomerID == "c2");
addc.City = "CD";
addc.ContactName = "cnblogs";
addc.Country = "CN";
int result = edm.SaveChanges();
Assert.AreEqual (result, 1);
Customers updatec = edm.Customers.FirstOrDefault(cc => cc.CustomerID == "c2");
Console.WriteLine("CustomerId={0},City={1}", updatec.CustomerID, updatec.City);
}
其中，需要注意的是：不能去更新主键，否则会报“System.InvalidOperationException : 属性“xxx”是对象的键信息的一部分，不能修改。”
l 删除：
实例代码如下：
using (var edm = new NorthwindEntities())
{
Customers deletec = edm.Customers.FirstOrDefault(cc => cc.CustomerID == "c2");
edm.DeleteObject(deletec);
int result = edm.SaveChanges();
Assert.AreEqual (result, 1);
Customers c = edm.Customers.FirstOrDefault(cc => cc.CustomerID == "c2");
Assert.AreEqual (c, null );
}
l 事务：
实例代码如下：
NorthwindEntities edm = null ;
System.Data.Common.DbTransaction tran = null ;
try
{
edm = new NorthwindEntities();
edm.Connection.Open();
tran = edm.Connection.BeginTransaction();
Customers cst = edm.Customers.FirstOrDefault(cc => cc.CustomerID == "c#");
cst.Country = "CN";
cst.City = "CD";
edm.SaveChanges();
tran.Commit();
}
catch (Exception ex)
{
if (tran != null )
tran.Rollback();
throw ex;
}
finally
{
if (edm != null && edm.Connection.State != System.Data.ConnectionState.Closed)
edm.Connection.Close();
}