// Nếu món tồn tại rồi thì chỉnh sửa BillInfor(new Quantity)
public void EditNewQuantityBillInfor(int QuantityAdd, int FoodID, int BillID)
{
TblBillInfor newBillInfor = new TblBillInfor();
newBillInfor = data.TblBillInfors.Single(n => n.BillID == BillID && n.FoodID == FoodID);
newBillInfor.CountF = GetFoodQuantity(FoodID, BillID) + QuantityAdd;
newBillInfor.Total = (GetFoodQuantity(FoodID, BillID) + QuantityAdd) * data.TblFoods.First(n => n.ID == FoodID).Price;
data.SaveChanges();
}
public void EditBillInfor(int Quantity, int FoodID, int BillID)
{
TblBillInfor newBillInfor = new TblBillInfor();
newBillInfor = data.TblBillInfors.Single(n => n.BillID == BillID && n.FoodID == FoodID);
newBillInfor.CountF = Quantity;
newBillInfor.Total = Quantity * data.TblFoods.First(n => n.ID == FoodID).Price;
data.SaveChanges();
}
// Nếu món ấy chưa tồn tại thì tạo BillInfor mới (input: IDBill+FoodID output: null)
public void AddBillInfor(int FoodID, int BillID, int Quantity)
{
TblBillInfor newBillInfor = new TblBillInfor()
{
BillID = BillID,
FoodID = FoodID,
CountF = Quantity,
Total = Quantity * data.TblFoods.First(n => n.ID == FoodID).Price
};
data.TblBillInfors.Add(newBillInfor);
data.SaveChanges();
}