public static void Demo_AddGraph()
{
CUI.Headline("Demo_AddGraph");
using (var ctx = new WWWingsContext())
{
ctx.Log();
ctx.Database.ExecuteSqlCommand("Delete from Booking where FlightNo = 101");
ctx.Database.ExecuteSqlCommand("Delete from Flight where FlightNo = 101");
var pilot = new Pilot();
pilot.Surname = "testpilot";
//ctx.PilotSet.Add(pilot);
var fneu = new Flight();
fneu.FlightNo = 101;
fneu.Departure = "Essen";
fneu.Destination = "Darmstadt";
fneu.Pilot = pilot;
fneu.Seats = 100;
fneu.Copilot = pilot;
fneu.FreeSeats = 100;
ctx.ChangeTracker.TrackGraph(fneu, (obj) => obj.NodeState = obj.Entry.State = EntityState.Added);
//ctx.ChangeTracker.TrackGraph(fneu, TrackGraph_CallbackAdded);
ctx.FlightSet.Add(fneu);
EFC_Util.PrintChangeInfo(ctx);
var anz = ctx.SaveChanges();
Console.WriteLine("Saved changes: " + anz);
}
}
public static void EF_ChangeTrackerAuswerten()
{
CUI.MainHeadline(nameof(EF_ChangeTrackerAuswerten));
using (WWWingsContext ctx = new WWWingsContext())
{
var f = ctx.FlightSet.FirstOrDefault();
Console.WriteLine("Before: " + f.ToString());
f.FreeSeats = (short)(new Random(DateTime.Now.Millisecond).Next(1, 100));
Console.WriteLine("After: " + f.ToString());
EFC_Util.PrintChangeInfo(ctx);
var anz = ctx.SaveChanges();
Console.WriteLine("Changes: " + anz);
}
}
public static void EF_ChangeTracking()
{
CUI.MainHeadline(nameof(EF_ChangeTracking));
using (WWWingsContext ctx = new WWWingsContext())
{
// kommt in nächster Version
//ctx.Configuration.AutoDetectChangesEnabled = false;
var f = ctx.FlightSet.FirstOrDefault();
Console.WriteLine("Before: " + f.ToString());
//Änderung
f.FreeSeats = (short)(new Random(DateTime.Now.Millisecond).Next(1, 100));
Console.WriteLine("After: " + f.ToString());
EFC_Util.PrintChangeInfo(ctx);
var anz = ctx.SaveChanges();
Console.WriteLine("Anzahl gespeicherter Ändeurngen: " + anz);
}
}
public static void ConflictWhileChangingFlight()
{
CUI.MainHeadline(nameof(ConflictWhileChangingFlight));
Console.WriteLine("Process.PersonID=" + Process.GetCurrentProcess().Id);
Console.Title = nameof(ConflictWhileChangingFlight) + ": Process-PersonID=" + Process.GetCurrentProcess().Id;
// Flight, where the conflict should arise
int flightNo = 151;
using (WWWingsContext ctx = new WWWingsContext())
{
// that is not possible: Read-only!
//ctx.Model.FindEntityType(typeof(Flight)).FindProperty("FreeSeats").IsConcurrencyToken = true;
// --- Load flight
Flight flight = ctx.FlightSet.Find(flightNo);
Console.WriteLine(DateTime.Now.ToLongTimeString() + ": free seats Before: " + flight.FreeSeats);
short seats = 0;
string input = "";
do
{
Console.WriteLine("How many seats do you need at this flight?");
input = Console.ReadLine(); // wait (time to start another process)
} while (!Int16.TryParse(input, out seats));
// --- change the free seats
flight.FreeSeats -= seats;
Console.WriteLine(DateTime.Now.ToLongTimeString() + ": free seats NEW: " + flight.FreeSeats);
try
{
// --- try to save
EFC_Util.PrintChangedProperties(ctx.Entry(flight));
var anz = ctx.SaveChanges();
Console.WriteLine("SaveChanges: Number of saved changes: " + anz);
}
catch (DbUpdateConcurrencyException ex)
{
Console.ForegroundColor = ConsoleColor.Red;
CUI.PrintError(DateTime.Now.ToLongTimeString() + ": Error: another user has already changed the flight!");
CUI.Print("Conflicts with the following properties:");
EFC_Util.PrintChangedProperties(ex.Entries.Single());
// --- Ask the user
Console.WriteLine("What do you want to do?");
Console.WriteLine("Key 1: Accept the values of the other user");
Console.WriteLine("Key 2: Override the values of the other user");
Console.WriteLine("Key 3: Calculate new value from both records");
ConsoleKeyInfo key = Console.ReadKey();
switch (key.Key)
{
case ConsoleKey.D1: // Accept the values of the other user
{
Console.WriteLine("You have chosen: Option 1: Accept");
ctx.Entry(flight).Reload();
break;
}
case ConsoleKey.D2: // Override the values of the other user
{
Console.WriteLine("You have chosen: Option 2: Override");
ctx.Entry(flight).OriginalValues.SetValues(ctx.Entry(flight).GetDatabaseValues());
// wie RefreshMode.ClientWins bei ObjectContext
EFC_Util.PrintChangeInfo(ctx);
int anz = ctx.SaveChanges();
Console.WriteLine("SaveChanges: Saved changes: " + anz);
break;
}
case ConsoleKey.D3: // Calculate new value from both records
{
Console.WriteLine("You have chosen: Option 3: Calculate");
var FreeSeatsOrginal = ctx.Entry(flight).OriginalValues.GetValue <short?>("FreeSeats");
var FreeSeatsNun = flight.FreeSeats.Value;
var FreeSeatsInDB = ctx.Entry(flight).GetDatabaseValues().GetValue <short?>("FreeSeats");
flight.FreeSeats = (short)(FreeSeatsOrginal -
(FreeSeatsOrginal - FreeSeatsNun) -
(FreeSeatsOrginal - FreeSeatsInDB));
EFC_Util.PrintChangeInfo(ctx);
ctx.Entry(flight).OriginalValues.SetValues(ctx.Entry(flight).GetDatabaseValues());
int anz = ctx.SaveChanges();
Console.WriteLine("SaveChanges: Saved changes: " + anz);
break;
}
}
}
Console.WriteLine(DateTime.Now.ToLongTimeString() + ": free seats after: " + flight.FreeSeats);
// --- Cross check the final state in the database
using (WWWingsContext ctx2 = new WWWingsContext())
{
var f = ctx.FlightSet.Where(x => x.FlightNo == flightNo).SingleOrDefault();
Console.WriteLine(DateTime.Now.ToLongTimeString() + ": free seats cross check: " + f.FreeSeats);
} // End using-Block -> Dispose()
}
}
/// <summary>
/// ConflictWhileChangingFlight
/// </summary>
public static void EF_Konflikt_BeiFlightMitVermeidungsOption(bool konfliktVermeidung = false)
{
CUI.MainHeadline(nameof(ConflictWhileChangingFlight));
Console.WriteLine("Process PersonID=" + Process.GetCurrentProcess().Id);
int flightNo = 151;
// Create context instance unter Verwendung der Verbindungszeichenfolge aus Konfigurationsdatei
using (WWWingsContext ctx = new WWWingsContext())
{
// das geht nicht: Read-only!
//ctx.Model.FindEntityType(typeof(Flight)).FindProperty("FreeSeats").IsConcurrencyToken = true;
ctx.Log(); // Protokollierung an der Konsole einschalten über eigene Erweiterungsmethode
// Load flight
Flight flight = null;
// optional: LeseSperre. Achtung: Worst Practices!!!
IDbContextTransaction t = null;
if (konfliktVermeidung)
{
t = ctx.Database.BeginTransaction(); // Standard ist System.Data.IsolationLevel.ReadCommitted
Console.WriteLine("Transaktion im Modus " + t.GetDbTransaction().IsolationLevel);
flight = ctx.FlightSet.FromSql("SELECT * FROM dbo.Flight WITH (UPDLOCK) WHERE FlightNo = {0}", flightNo).SingleOrDefault();
}
else
{
flight = ctx.FlightSet.SingleOrDefault(x => x.FlightNo == flightNo);
}
Console.WriteLine(DateTime.Now.ToLongTimeString() + ": free seats Before: " + flight.FreeSeats);
Console.ReadLine(); // Warten (zum Starten eines zweiten Processes!)
// Änderung
flight.FreeSeats = (short)(new Random(DateTime.Now.Millisecond).Next(1, 100));
Console.WriteLine(DateTime.Now.ToLongTimeString() + ": free seats NEW: " + flight.FreeSeats);
try
{
// Speicherversuch
EFC_Util.PrintChangedProperties(ctx.Entry(flight));
ctx.SaveChanges();
}
catch (DbUpdateConcurrencyException ex)
{
Console.ForegroundColor = ConsoleColor.Red;
CUI.PrintError(DateTime.Now.ToLongTimeString() + ": Error: Ein anderer Benutzer has bereits geändert!");
CUI.Print("Konflikte bei folgenden Eigenschaften:");
EFC_Util.PrintChangedProperties(ex.Entries.Single());
// Frage beim Benutzer nach
Console.WriteLine(
"Möchten Sie den Wert des anderen Benutzers übernehmen (Taste '1') oder überschreiben (Taste '2')?");
ConsoleKeyInfo key = Console.ReadKey();
if (key.Key == ConsoleKey.D1)
{
Console.WriteLine("Sie haben gewählt: Option 1: übernehmen");
// Werte des anderen Benutzers übernehmen
ctx.Entry(flight).Reload(); // wie RefreshMode.StoreWins bei ObjectContext
}
else
{
Console.WriteLine("Sie haben gewählt: Option 2: überschreiben");
Console.ForegroundColor = ConsoleColor.Gray;
// Werte des anderen Benutzers überschreiben
ctx.Entry(flight).OriginalValues.SetValues(ctx.Entry(flight).GetDatabaseValues());
// wie RefreshMode.ClientWins bei ObjectContext
EFC_Util.PrintChangeInfo(ctx);
int anz = ctx.SaveChanges();
Console.WriteLine("SaveChanges: Saved changes: " + anz);
}
}
Console.WriteLine(DateTime.Now.ToLongTimeString() + ": FreeSeats After: " + flight.FreeSeats);
if (konfliktVermeidung)
{
t.Commit();
}
using (WWWingsContext ctx2 = new WWWingsContext())
{
var f = ctx.FlightSet.Where(x => x.FlightNo == flightNo).SingleOrDefault();
Console.WriteLine(DateTime.Now.ToLongTimeString() + ": FreeSeats: " + f.FreeSeats);
} // End using-Block -> Dispose()
}
}
