private static void 示範實體狀態用法(ContosoUniversityEntities db)
{
var one = db.Course.Find(14);
db.Entry(one).State = System.Data.Entity.EntityState.Modified;
db.SaveChanges();
var c = new Course()
{
CourseID = 14
};
db.Entry(c).State = System.Data.Entity.EntityState.Deleted;
db.Course.Remove(c);
db.SaveChanges();
Console.WriteLine(db.Entry(one).State);
one.Credits += 1;
Console.WriteLine(db.Entry(one).State);
//db.Entry(one).State = System.Data.Entity.EntityState.Deleted;
db.SaveChanges();
Console.WriteLine(db.Entry(one).State);
}
private static void SaveChangesWithEntityStates(ContosoUniversityEntities db)
{
var c = new Course
{
Title = "Entity Framework 6.1",
Credits = 10,
Department = db.Department.Find(1)
};
db.Course.Add(c);
db.SaveChanges();
var id = c.CourseID;
db.Entry(c).State = System.Data.Entity.EntityState.Modified;
db.SaveChanges();
db.Entry(c).State = System.Data.Entity.EntityState.Detached;
var d = new Course {
CourseID = id
};
db.Entry(d).State = System.Data.Entity.EntityState.Deleted;
db.SaveChanges();
}
private static void DeleteCourse(ContosoUniversityEntities db)
{
var course = db.Course.Find(9);
db.Course.Remove(course);
db.SaveChanges();
}
private static void ShowEntityStates(ContosoUniversityEntities db)
{
var one = db.Course.Find(11);
Console.WriteLine(db.Entry(one).State);
one.Credits += 10;
Console.WriteLine(db.Entry(one).State);
db.Course.Remove(one);
Console.WriteLine(db.Entry(one).State);
db.SaveChanges();
Console.WriteLine(db.Entry(one).State);
}
private static void AddCourse(ContosoUniversityEntities db)
{
var course = new Course
{
Title = "Entity Framework 6",
Credits = 100
};
course.Department = db.Department.Find(2);
db.Course.Add(course);
db.SaveChanges();
}
private static void UpdateCourse(ContosoUniversityEntities db)
{
var courses = db.Course.Where(c => c.Title.Contains("Git"));
foreach (var course in courses)
{
course.Credits += 10;
course.CreatedOn = DateTime.Now;
course.UpdatedOn = DateTime.Now;
}
db.SaveChanges();
}
private static void UpdateCourse(ContosoUniversityEntities db)
{
var items = db.Course.Where(p => p.Title.Contains("Git"));
foreach (var item in items)
{
item.Credits += 1;
item.CreatedOn = DateTime.Now;
item.UpdatedOn = DateTime.Now;
}
db.SaveChanges();
}
private static void AddCourse(ContosoUniversityEntities db)
{
var c = new Course()
{
Title = "Entity Framework 6.1",
Credits = 100,
IsDeleted = false
};
c.Department = db.Department.Find(2);
db.Course.Add(c);
db.SaveChanges();
}
private static void DeleteCourse(ContosoUniversityEntities db)
{
//var c = db.Course.Find(9);
//var c = db.Course.FirstOrDefault(p => p.Title.StartsWith("Git"));
//db.Course.Remove(c);
var c = db.Course.Where(p => p.Title.StartsWith("Git"));
db.Course.RemoveRange(c);
db.SaveChanges();
}