public void Solution4B()
{
var myDevice = new Device {
Id = 99999, Name = "My Radio"
};
using (var context = new RadioContext())
{
try
{
context.Configuration.AutoDetectChangesEnabled = false;
context.Devices.Add(myDevice);
var entities = context.ChangeTracker.Entries();
Device device = context.Devices.AsNoTracking().First();
entities = context.ChangeTracker.Entries();
device.Firmware = "10.0.0.0";
WriteOutput($"{context.Entry(myDevice).State}");
WriteOutput($"{context.Entry(device).State}");
device.Firmware = "10.0.0.0";
WriteOutput($"{context.Entry(device).State}");
}
finally
{
context.Configuration.AutoDetectChangesEnabled = true;
}
}
}
public void Example6()
{
int userId = 2009;
string firstName = "Marcin";
string lastName = "Sulecki";
using (var context = new RadioContext())
{
User user = context.Contacts
.OfType <User>()
.Single(c => c.Id == userId);
WriteOutput(context.Entry(user).State.ToString());
user.FirstName = firstName;
user.LastName = lastName;
WriteOutput(context.Entry(user).State.ToString());
context.SaveChanges();
WriteOutput(context.Entry(user).State.ToString());
user.Country = "Poland";
WriteOutput(context.Entry(user).State.ToString());
context.SaveChanges();
WriteOutput(context.Entry(user).State.ToString());
}
}
public void Example4B()
{
var myDevice = new Device {
Id = 99999, Name = "My Radio"
};
using (var context = new RadioContext())
{
context.Configuration.AutoDetectChangesEnabled = true; // domyślnie włączone
context.Devices.Add(myDevice);
var entities = context.ChangeTracker.Entries();
Device device = context.Devices.AsNoTracking().First();
entities = context.ChangeTracker.Entries();
device.Firmware = "10.0.0.0";
WriteOutput($"{context.Entry(myDevice).State}");
WriteOutput($"{context.Entry(device).State}");
device.Firmware = "10.0.0.0";
WriteOutput($"{context.Entry(device).State}");
}
}
public void Solution9B()
{
string country = "Poland";
var config = new MapperConfiguration(
cfg => cfg.CreateMap <User, UserDTO>()
.ForMember(dest => dest.Surname, opt => opt.MapFrom(src => src.LastName)));
var mapper = config.CreateMapper();
using (var context = new RadioContext())
{
IQueryable <UserDTO> users = context.Contacts
.OfType <User>()
.Where(u => u.Country == country)
.ProjectTo <UserDTO>(config)
.OrderBy(u => u.Surname);
List <UserDTO> userDTOs = users.ToList();
var userDTO = userDTOs.First();
WriteOutput(context.Entry(userDTO).State.ToString());
}
}
public void Example4A()
{
using (var context = new RadioContext())
{
Device device = context.Devices.First();
// Wyświetlenie stacji encji
WriteOutput($"{context.Entry(device).State}");
}
}
public void Solution4A()
{
using (var context = new RadioContext())
{
Device device = context
.Devices
.AsNoTracking() // wyłączenie śledzenie zmian
.First();
WriteOutput($"{context.Entry(device).State}");
}
}
public void Solution6B()
{
int userId = 747474;
string firstName = "Bartek";
string lastName = "Sulecki";
string country = "Country";
string companyName = "Altkom";
// symulacja deserializacji
User user = new User
{
Id = userId,
FirstName = firstName,
LastName = lastName,
Country = country,
CompanyName = companyName
};
using (var context = new RadioContext())
{
WriteOutput(context.Entry(user).State.ToString());
context.Contacts.Attach(user);
WriteOutput(context.Entry(user).State.ToString());
context.Entry(user).State = System.Data.Entity.EntityState.Modified;
WriteOutput(context.Entry(user).State.ToString());
var entities = context.ChangeTracker.Entries()
.Select(x => new { x.Entity, x.State });
context.SaveChanges();
WriteOutput(context.Entry(user).State.ToString());
}
}
public void Solution11A()
{
using (var context1 = new RadioContext())
using (var context2 = new RadioContext())
{
context1.Database.Log += msg => WriteOutput(msg, ConsoleColor.Green);
context2.Database.Log += msg => WriteOutput(msg, ConsoleColor.Blue);
Random random = new Random();
// user 1
var contact1 = context1.Contacts.Find(contactId);
contact1.CompanyName = $"Altkom {random.Next(1, 100)}";
try
{
// user 2
var contact2 = context2.Contacts.Find(contactId);
contact2.CompanyName = $"Motorola {random.Next(1, 100)}";
context2.SaveChanges();
// user 1
context1.SaveChanges();
}
catch (DbUpdateConcurrencyException e)
{
WriteOutput("Another user was changed data", ConsoleColor.Red);
// var original = context1.Entry(contact1).OriginalValues.ToObject();
var my = context1.Entry(contact1).CurrentValues.ToObject();
// Refresh object from database
context1.Entry(contact1).Reload();
var current = context1.Entry(contact1).OriginalValues.ToObject();
}
}
}
// Usuwanie encji za pomocą bezpośredniej zmiany stanu
public void Solution6C()
{
int userId = 1000;
User user = new User {
Id = userId
};
using (var context = new RadioContext())
{
context.Contacts.Attach(user);
context.Entry(user).State = EntityState.Deleted;
context.SaveChanges();
}
}
public void Solution6A()
{
int userId = 2009;
string firstName = "Bartek";
string lastName = "Sulecki";
using (var context = new RadioContext())
{
context.Configuration.AutoDetectChangesEnabled = false;
User user = context.Contacts
.AsNoTracking()
.OfType <User>()
.Single(c => c.Id == userId);
// TODO: Long process
WriteOutput(context.Entry(user).State.ToString());
context.Contacts.Attach(user);
user.FirstName = firstName;
user.LastName = lastName;
WriteOutput(context.Entry(user).State.ToString());
WriteOutput(context.Entry(user).State.ToString());
context.ChangeTracker.DetectChanges();
WriteOutput(context.Entry(user).State.ToString());
context.SaveChanges();
WriteOutput(context.Entry(user).State.ToString());
user.Country = "Poland";
WriteOutput(context.Entry(user).State.ToString());
context.SaveChanges();
WriteOutput(context.Entry(user).State.ToString());
}
}