public void get_and_update_multiple_context_bad()
{
UserTestData.PrepareUser(userId);
var newUsername = $"new-username-{Guid.NewGuid().ToString("n")}";
User user;
using (var db = new MyContext())
{
user = db.Users.Find(userId);
}
if (user.UserName != newUsername)
{
user.UserName = newUsername;
}
using (var db = new MyContext())
{
user.UserName = newUsername;
db.SaveChanges();
}
using (var db = new MyContext())
{
var user1 = db.Users.Find(userId);
// the assingment won't do anything, since the user object is from another context
Assert.AreNotEqual(newUsername, user1.UserName);
}
}
public void get_and_update_single_context()
{
UserTestData.PrepareUser(userId);
string lastUsername = "";
perfMeter.MeasurePerf(() =>
{
var newUsername = $"new-username-{Guid.NewGuid().ToString("n")}";
using (var db = new MyContext())
{
var user = db.Users.Find(userId);
if (user.UserName != newUsername)
{
user.UserName = newUsername;
}
db.SaveChanges();
}
lastUsername = newUsername;
});
using (var db = new MyContext())
{
var user1 = db.Users.Find(userId);
Assert.AreEqual(lastUsername, user1.UserName);
}
}
public void get_and_add_to_collection_multiple_context_reattach()
{
UserTestData.PrepareUser(userId);
int originalCount = 0;
using (var db = new MyContext())
{
var user = db.Users.Find(userId);
originalCount = user.Orders.Count();
}
perfMeter.MeasurePerf(() =>
{
User user;
using (var db = new MyContext())
{
user = db.Users.Find(userId);
db.Entry(user).Collection(u => u.Orders).Load();
}
// if orders are not loaded, then:
// The ObjectContext instance has been disposed and can no longer be used for operations that require a connection.
var newOrder = new Order("item-1")
{
User = user,
// setting user is not enough:
UserId = user.Id
};
user.Orders.Add(newOrder);
using (var db = new MyContext())
{
// the new context don't see changes in related collection (user.Orders)
db.Users.Attach(user);
db.Entry(user).State = System.Data.Entity.EntityState.Modified;
db.SaveChanges();
}
});
using (var db = new MyContext())
{
var user = db.Users.Find(userId);
var newCount = user.Orders.Count();
Assert.AreEqual(originalCount + perfMeter.LoopsCount, newCount);
}
}
public void get_and_add_to_dbset_multiple_contexts()
{
UserTestData.PrepareUser(userId);
int originalCount = 0;
using (var db = new MyContext())
{
var user = db.Users.Find(userId);
originalCount = user.Orders.Count();
}
perfMeter.MeasurePerf(() =>
{
User user;
using (var db = new MyContext())
{
user = db.Users.Find(userId);
}
var newOrder = new Order("item-1")
{
// setting the user here will make EF see it as a newly added object
// alterntively, user can be reattached to the new cntext
// User = user
UserId = userId
};
using (var db = new MyContext())
{
db.Orders.Add(newOrder);
db.SaveChanges();
}
});
using (var db = new MyContext())
{
var user = db.Users.Find(userId);
var newCount = user.Orders.Count();
Assert.AreEqual(originalCount + perfMeter.LoopsCount, newCount);
}
}
public void get_and_add_to_collection_single_context()
{
UserTestData.PrepareUser(userId);
int originalCount = 0;
using (var db = new MyContext())
{
var user = db.Users.Find(userId);
originalCount = user.Orders.Count();
}
perfMeter.MeasurePerf(() =>
{
User user;
using (var db = new MyContext())
{
user = db.Users.Find(userId);
// if orders are not loaded, then:
// The ObjectContext instance has been disposed and can no longer be used for operations that require a connection.
var newOrder = new Order("item-1")
{
// no need to sest user or userid
};
// this will load all user's orders... :(
user.Orders.Add(newOrder);
db.SaveChanges();
}
});
using (var db = new MyContext())
{
var user = db.Users.Find(userId);
var newCount = user.Orders.Count();
Assert.AreEqual(originalCount + perfMeter.LoopsCount, newCount);
}
}
public void get_and_update_multiple_context_reattach()
{
UserTestData.PrepareUser(userId);
string lastUsername = "";
perfMeter.MeasurePerf(() =>
{
var newUsername = $"new-username-{Guid.NewGuid().ToString("n")}";
User user;
using (var db = new MyContext())
{
user = db.Users.Find(userId);
}
if (user.UserName != newUsername)
{
user.UserName = newUsername;
}
using (var db = new MyContext())
{
db.Users.Attach(user);
db.Entry(user).State = System.Data.Entity.EntityState.Modified;
user.UserName = newUsername;
db.SaveChanges();
}
lastUsername = newUsername;
});
using (var db = new MyContext())
{
var user1 = db.Users.Find(userId);
Assert.AreEqual(lastUsername, user1.UserName);
}
}
public void get_and_add_to_dbset_single_context()
{
UserTestData.PrepareUser(userId);
int originalCount = 0;
using (var db = new MyContext())
{
var user = db.Users.Find(userId);
originalCount = user.Orders.Count();
}
perfMeter.MeasurePerf(() =>
{
User user;
using (var db = new MyContext())
{
user = db.Users.Find(userId);
var newOrder = new Order("item-1")
{
User = user
};
db.Orders.Add(newOrder);
db.SaveChanges();
}
});
using (var db = new MyContext())
{
var user = db.Users.Find(userId);
var newCount = user.Orders.Count();
Assert.AreEqual(originalCount + perfMeter.LoopsCount, newCount);
}
}
private void PrepareUser(int userId) => UserTestData.PrepareUser(userId);