public async Task CRUDUsingLINQ()
{
// The ConfigFactory static constructor reads the "MyProjectSettings" from appsettings.json
// or secrets.json and exposes the IUserConfiguration interface. We use that interface
// to retrieve the connection string mapped to the DatabaseName.
string ConnectionString = _requirements.UserConfiguration.ConnectionString("DSuite");
DbContextOptionsBuilder <DSuiteContext> optionsBuilder = new DbContextOptionsBuilder <DSuiteContext>();
optionsBuilder.UseSqlServer(ConnectionString);
DSuiteContext dSuiteContext = new DSuiteContext(optionsBuilder.Options);
// NOTE: All the code above could be replaced with a single line of code.
// We write out the code here just to show you what's going on
// under the covers:
//
// DSuiteContext dSuiteContext = DBContextFactory.GetDbContext<DSuiteContext>();
// Equivalent CRUD using just linq
Car newCar = GenerateCar();
dSuiteContext.Cars.Add(newCar);
await dSuiteContext.SaveChangesAsync();
Car found = (from c in dSuiteContext.Cars where c.CarId == newCar.CarId select c).SingleOrDefault();
dSuiteContext.Remove(found);
await dSuiteContext.SaveChangesAsync();
}
public static async Task PopulateDummyCars(int NumberOfCars)
{
// Ask the DBContextFactory to create the desired DbContext object for use for database access
DSuiteContext db = DBContextFactory.GetDbContext <DSuiteContext>();
for (int i = 0; i < NumberOfCars; ++i)
{
Car NewCar = GenerateCar();
await EFCrud.Create(db, NewCar);
}
}
public async Task CRUDUsingHelperClass()
{
Car newCar = GenerateCar();
// Demonstrate basic CRUD
DSuiteContext db = DBContextFactory.GetDbContext <DSuiteContext>();
await EFCrud.Create(db, newCar);
Car found = await EFCrud.GetByKey(db, newCar);
EFCrud.Delete(db, found);
}
public void FindMultipleUsingHelperClass(DSuiteContext dSuite)
{
// Demonstrate the deferred execution POWER of IQueryable!
// Find a small list of cars that we don't need to page through.
IQueryable <Car> fordBunnies = dSuite.FindMultiple <Car, DSuiteContext>((x) => x.Make == "Ford" && x.Model == "Bunny" && x.Year < 2006, x => x.Year);
// But I DO want to sort them too. Still no DB call here!
fordBunnies = fordBunnies.OrderBy(bunny => bunny.Mileage);
// NOW, go ahead and execute the query against the database
fordBunnies.DumpData($"\r\n\r\n==============FindMultipleUsingHelperClass==============================");
}
public static Car Delete(Car ToDelete, DSuiteContext db)
{
Car Deleted = null;
if (ToDelete != null)
{
db.Cars.Remove(ToDelete);
db.SaveChanges();
Deleted = ToDelete;
}
return(Deleted);
}
public void FindMultipleUsingLINQ()
{
DSuiteContext dSuiteContext = DBContextFactory.GetDbContext <DSuiteContext>();
// Demonstrate the deferred execution POWER of IQueryable!
// Find a small list of cars that we don't need to page through.
IQueryable <Car> linqFordBunnies = (from c in dSuiteContext.Cars where c.Make == "Ford" && c.Model == "Bunny" && c.Year < 2006 select c);
// But I DO want to sort them too. Still no DB call here!
linqFordBunnies = linqFordBunnies.OrderBy(bunny => bunny.Mileage);
// NOW, go ahead and execute the query against the database
linqFordBunnies.DumpData("\r\n\r\n==============FindMultipleUsingLINQ==============================");
}
public static Car Add(Car NewCar, DSuiteContext db)
{
try
{
db.Cars.Add(NewCar);
db.SaveChanges();
}
catch (Exception Err)
{
_Logger.LogError(Err, "Could not add car");
}
return(NewCar);
}
public static Car Delete(int id, DSuiteContext db)
{
Car Deleted = null;
try
{
Car ToDelete = Get(id, db);
Deleted = Delete(ToDelete, db);
}
catch (Exception Err)
{
_Logger.LogError(Err, "Could not delete car");
}
return(Deleted);
}
public static Car Update(Car Update, DSuiteContext db)
{
try
{
Car myCar = (from c in db.Cars where c.CarId == Update.CarId select c).FirstOrDefault();
if (myCar != null)
{
db.Entry(myCar).CurrentValues.SetValues(Update);
db.SaveChanges();
}
}
catch (Exception Err)
{
_Logger.LogError(Err, "Could not update car");
}
return(Update);
}
/// <summary>
/// Application initialization.
/// </summary>
/// <param name="requirements">IApplicationRequirements Supplied by DI. All required interfaces</param>
/// <param name="dSuiteContext">DbContext for DSuite database</param>
/// <param name="schoolContext">DbContext for School database</param>
/// <param name="cars">ICarRepository Example of using repository pattern</param>
/// <param name="courses">ICourseRepository Example of using repository pattern</param>
/// <param name="students">IStudentsRepository Example of using repository pattern</param>
/// <param name="enrollments">IEnrollmentsRepository Example of using repository pattern</param>
public MyApplication(IApplicationRequirements <MyApplication> requirements,
DSuiteContext dSuiteContext,
SchoolContext schoolContext,
ICarRepository cars,
ICourseRepository courses,
IStudentRepository students,
IEnrollmentRepository enrollments,
IDataRepository <Student, int, SchoolContext> genericStudentDataRepository
)
{
_requirements = requirements;
_dSuite = dSuiteContext;
_school = schoolContext;
_cars = cars;
_courses = courses;
_students = students;
_enrollments = enrollments;
// Same as the _students interface, except it's an open generic type
_genericStudentDataRepository = genericStudentDataRepository;
EFCrud.InitializeLogger(_requirements.ApplicationLogger);
EFHelper.InitializeLogger(_requirements.ApplicationLogger);
}
public static Car Get(int id, DSuiteContext db)
{
Car myCar = (from c in db.Cars where c.CarId == id select c).FirstOrDefault();
return(myCar);
}
public static Car Get(Car toGet, DSuiteContext db)
{
return(Get(toGet.CarId, db));
}
