private static void SaveDestinationAndLodgings(
Destination destination,
List <Lodging> deletedLodgings)
{
// TODO: Ensure only Destinations & Lodgings are passed in
using (var context = new BreakAwayContext())
{
context.Destinations.Add(destination);
if (destination.DestinationId > 0)
{
context.Entry(destination).State = EntityState.Modified;
}
foreach (var lodging in destination.Lodgings)
{
if (lodging.LodgingId > 0)
{
context.Entry(lodging).State = EntityState.Modified;
}
}
foreach (var lodging in deletedLodgings)
{
context.Entry(lodging).State = EntityState.Deleted;
}
context.SaveChanges();
}
}
private static void AddSimpleGraph()
{
var essex = new Destination
{
Name = "Essex, Vermont",
Lodgings = new List <Lodging>
{
new Lodging {
Name = "Big Essex Hotel"
},
new Lodging {
Name = "Essex Junction B&B"
},
}
};
using (var context = new BreakAwayContext())
{
context.Destinations.Add(essex);
Console.WriteLine("Essex Destination: {0}", context.Entry(essex).State);
foreach (var lodging in essex.Lodgings)
{
Console.WriteLine("{0}: {1}",
lodging.Name,
context.Entry(lodging).State);
}
context.SaveChanges();
}
}
private static void DeleteDestinationInMemoryAndDbCascade()
{
int destinationId;
using (var context = new BreakAwayContext())
{
var destination = new Destination
{
Name = "Sample Destination",
Lodgings = new List <Lodging>
{
new Lodging {
Name = "Lodging One"
},
new Lodging {
Name = "Lodging Two"
}
}
};
context.Destinations.Add(destination);
context.SaveChanges();
destinationId = destination.DestinationId;
}
using (var context = new BreakAwayContext())
{
var destination = context.Destinations
.Include("Lodgings")
.Single(d => d.DestinationId == destinationId);
var aLodging = destination.Lodgings.FirstOrDefault();
context.Destinations.Remove(destination);
Console.WriteLine("State of one Lodging: {0}",
context.Entry(aLodging).State.ToString());
context.SaveChanges();
}
}
private static void CreatingNewProxies()
{
using (var context = new BreakAwayContext())
{
var nonProxy = new Destination();
nonProxy.Name = "Non-proxy Destination";
nonProxy.Lodgings = new List <Lodging>();
var proxy = context.Destinations.Create();
proxy.Name = "Proxy Destination";
context.Destinations.Add(proxy);
context.Destinations.Add(nonProxy);
var davesDump = (from l in context.Lodgings
where l.Name == "Dave's Dump"
select l).Single();
context.Entry(davesDump)
.Reference(l => l.Destination)
.Load();
Console.WriteLine("Before changes: {0}", davesDump.Destination.Name);
nonProxy.Lodgings.Add(davesDump);
Console.WriteLine("Added to non-proxy destination: {0}", davesDump.Destination.Name);
proxy.Lodgings.Add(davesDump);
Console.WriteLine("Added to proxy destination: {0}", davesDump.Destination.Name);
}
}
private static void ManualDetectChanges()
{
using (var context = new BreakAwayContext())
{
context.Configuration.AutoDetectChangesEnabled = false;
var reef = (from d in context.Destinations
where d.Name == "Great Barrier Reef"
select d).Single();
reef.Description = "The world's largest reef!";
Console.WriteLine("Before DetectChanges: {0}", context.Entry(reef).State);
context.ChangeTracker.DetectChanges();
Console.WriteLine("After DetectChanges: {0}", context.Entry(reef).State);
}
}
private static void UpdateLodging(Lodging lodging)
{
using (var context = new BreakAwayContext())
{
context.Entry(lodging).State = EntityState.Modified;
context.SaveChanges();
}
}
private static void UpdateDestination(Destination destination)
{
using (var context = new BreakAwayContext())
{
context.Entry(destination).State = EntityState.Modified;
context.SaveChanges();
}
}
private static void AttachDestination(Destination destination)
{
using (var context = new BreakAwayContext())
{
context.Entry(destination).State = EntityState.Unchanged;
context.SaveChanges();
}
}
/// <summary>
/// 这个功能演示联级删除 Annotation
/// </summary>
static void DeleteDestinationInMemoryAndDbCascade()
{
Guid destinationId;
using (var context = new BreakAwayContext())
{
var destination = new AnnotationModel.Destination
{
Name = "Sample Destination",
Address = new AnnotationModel.Address
{
City = "City",
StreetAddress = "StreetAddress",
State = "State",
ZipCode = "ZipCode"
},
Info = new AnnotationModel.PersonalInfo
{
DietryRestrictions = "DietryRestrictions",
Height = new AnnotationModel.Measurement
{
Reading = 0.1M,
Units = "0.2"
},
Width = new AnnotationModel.Measurement
{
Reading = 1.1M,
Units = "1.2"
}
},
Lodgings = new List <AnnotationModel.Lodging>
{
new AnnotationModel.Lodging
{
Name = "Lodging One"
},
new AnnotationModel.Lodging
{
Name = "Lodging Two"
}
}
};
context.Destinations.Add(destination);
context.SaveChanges();
destinationId = destination.DestinationId;
}
using (var context = new BreakAwayContext())
{
var destination = context.Destinations.Include("Lodgings").Single(d => d.DestinationId == destinationId);
var aLodging = destination.Lodgings.FirstOrDefault();
context.Destinations.Remove(destination);
Console.WriteLine("State of one Lodging: {0}", context.Entry(aLodging).State.ToString());
context.SaveChanges();
}
}
public ActionResult Edit([Bind(Include = "LodgingId,Name,Owner,IsResort,MilesFromNearestAirport,LocationId")] Lodging lodging)
{
if (ModelState.IsValid)
{
db.Entry(lodging).State = EntityState.Modified;
db.SaveChanges();
return(RedirectToAction("Index"));
}
return(View(lodging));
}
public ActionResult Edit([Bind(Include = "Identifier,StartDate,EndDate,CostUSD,RowVersion")] Trip trip)
{
if (ModelState.IsValid)
{
db.Entry(trip).State = EntityState.Modified;
db.SaveChanges();
return(RedirectToAction("Index"));
}
return(View(trip));
}
public ActionResult Edit([Bind(Include = "SocialSecurityNumber,FirstName,LastName,RowVersion,Info,Address")] Person person)
{
if (ModelState.IsValid)
{
db.Entry(person).State = EntityState.Modified;
db.SaveChanges();
return(RedirectToAction("Index"));
}
return(View(person));
}
public ActionResult Edit([Bind(Include = "DestinationId,Name,Country,Description,Photo")] Destination destination)
{
if (ModelState.IsValid)
{
db.Entry(destination).State = EntityState.Modified;
db.SaveChanges();
return(RedirectToAction("Index"));
}
return(View(destination));
}
// Auslesen der Validationsmeldungen die durch eine Entity produziert werden.
private static void ConsoleValidationResult(object entity)
{
using (var context = new BreakAwayContext())
{
var result = context.Entry(entity).GetValidationResult();
foreach (DbValidationError error in result.ValidationErrors)
{
Console.WriteLine(error.ErrorMessage);
}
}
}
private static void DeleteDestination(int destinationId)
{
using (var context = new BreakAwayContext())
{
var destination = new Destination {
DestinationId = destinationId
};
context.Entry(destination).State = EntityState.Deleted;
context.SaveChanges();
}
}
public ActionResult Edit([Bind(Include = "LodgingId,Name,Owner,IsResort,MilesFromNearestAirport,DestinationId,Entertainment,Activities")] Resort resort)
{
if (ModelState.IsValid)
{
db.Entry(resort).State = EntityState.Modified;
db.SaveChanges();
return(RedirectToAction("Index"));
}
ViewBag.DestinationId = new SelectList(db.Destinations, "DestinationId", "Name", resort.DestinationId);
return(View(resort));
}
private static void PrintState()
{
using (var context = new BreakAwayContext())
{
var canyon = (from d in context.Destinations
where d.Name == "Grand Canyon"
select d).Single();
DbEntityEntry <Destination> entry = context.Entry(canyon);
Console.WriteLine("Before Edit: {0}", entry.State);
canyon.TravelWarnings = "Take lots of water.";
Console.WriteLine("After Edit: {0}", entry.State);
}
}
private static void TestIsLoaded()
{
using (var context = new BreakAwayContext())
{
var canyon = (from d in context.Destinations
where d.Name == "Grand Canyon"
select d).Single();
var entry = context.Entry(canyon);
Console.WriteLine("Before Load: {0}", entry.Collection(d => d.Lodgings).IsLoaded);
entry.Collection(d => d.Lodgings).Load();
Console.WriteLine("After Load: {0}", entry.Collection(d => d.Lodgings).IsLoaded);
}
}
private static void QueryLodgingCount()
{
using (var context = new BreakAwayContext())
{
var canyonQuery = from d in context.Destinations
where d.Name == "Grand Canyon"
select d;
var canyon = canyonQuery.Single();
var lodgingQuery = context.Entry(canyon)
.Collection(d => d.Lodgings)
.Query();
var lodgingCount = lodgingQuery.Count();
Console.WriteLine("Lodging at Grand Canyon: " + lodgingCount);
}
}
// Explicit Loading
private static void TestExplicitLoading()
{
using (var context = new BreakAwayContext())
{
var query = from d in context.Destinations
where d.Name == "Grand Canyon"
select d;
var canyon = query.SingleOrDefault();
context.Entry(canyon).Collection(d => d.Lodgings).Load();
System.Console.WriteLine("Grabd Canyon Lodging");
foreach (var lodging in canyon.Lodgings)
{
System.Console.WriteLine(lodging.Name);
}
}
}
private static void PrintChangeTrackingInfo(BreakAwayContext context,
Lodging entity)
{
var entry = context.Entry(entity);
if (entry.State == EntityState.Deleted)
{
Console.WriteLine("\nCurrent Values:");
PrintPropertyValues(entry.CurrentValues);
}
if (entry.State == EntityState.Added)
{
Console.WriteLine("\nOriginal Values:");
PrintPropertyValues(entry.OriginalValues);
Console.WriteLine("\nDatabase Values:");
PrintPropertyValues(entry.GetDatabaseValues());
}
}
public void ValidationDetectsMissingPhotoInPerson()
{
var person = new Person
{
FirstName = "Mikael",
LastName = "Eliasson"
};
DbEntityValidationResult result;
using (var context = new BreakAwayContext())
{
result = context.Entry(person).GetValidationResult();
}
Assert.IsFalse(result.IsValid);
Assert.IsTrue(result.ValidationErrors
.Any(v => v.ErrorMessage.ToLower()
.Contains("photo field is required")));
}
private static void DetectRelationshipChanges()
{
using (var context = new BreakAwayContext())
{
var hawaii = (from d in context.Destinations
where d.Name == "Hawaii"
select d).Single();
var davesDump = (from l in context.Lodgings
where l.Name == "Dave's Dump"
select l).Single();
context.Entry(davesDump)
.Reference(l => l.Destination)
.Load();
hawaii.Lodgings.Add(davesDump);
Console.WriteLine("Before DetectChanges: {0}", davesDump.Destination.Name);
context.ChangeTracker.DetectChanges();
Console.WriteLine("After DetectChanges: {0}", davesDump.Destination.Name);
}
}
/* Chapter 6 Validation API
*
* Validating a Single Object on Demand with GetValidationResult
* ------------------------------------------------------------
*
* In Destionation Class
* -------------------------------------------
* [MaxLength(10)]
* public string LastName { get; set; }
* ---------------------------------------------
*
* Now let’s see what happens when we set the length to a string with more than ten
* characters. GetValidationResult allows you to explicitly validate a single entity. It returns
* a ValidationResult type that contains three important members. We’ll focus on
* just one of those for now, the IsValid property, which is a Boolean that indicates if the
* instance passed its validation rules. Let’s use that to validate a Person instance.
*
*
*
*/
private static void ValidateNewPerson()
{
var person = new Person
{
FirstName = "Julie",
LastName = "Lerman",
Photo = new PersonPhoto {
Photo = new Byte[] { 0 }
}
};
using (var context = new BreakAwayContext())
{
if (context.Entry(person).GetValidationResult().IsValid)
{
Console.WriteLine("Person is Valid");
}
else
{
Console.WriteLine("Person is Invalid");
}
}
}
private static void QueryLodgingDistance()
{
using (var context = new BreakAwayContext())
{
var canyonQuery = from d in context.Destinations
where d.Name == "Grand Canyon"
select d;
var canyon = canyonQuery.Single();
var lodgingQuery = context.Entry(canyon)
.Collection(d => d.Lodgings)
.Query();
var distanceQuery = from l in lodgingQuery
where l.MilesFromNearestAirport <= 10
select l;
foreach (var lodging in distanceQuery)
{
Console.WriteLine(lodging.Name);
}
}
}