public void ProcessContinue(int id, Reader reader)
{
using (var db = new SSLSEntities())
{
using (var dbContextTransaction = db.Database.BeginTransaction())
{
try
{
Borrow borrow = db.Borrow.FirstOrDefault(c => c.BookId == id && c.ReaderId == reader.Id);
borrow.ShouldReturnDate = DateTime.Now.AddDays(30);
db.SaveChanges();
dbContextTransaction.Commit();
}
catch (Exception)
{
dbContextTransaction.Rollback();
}
}
}
}
//归还业务
/*
* 归还业务应该只改写borrow的数据状态，至于罚款业务有专门的ProcessPayFine负责
*/
public void ProcessReturn(Book book, Reader reader)
{
//db是一个具有各项模型属性的上下文类
using (var db = new 校园自助图书管理系统Entities())
{
//创建事务
using (var dbContextTransaction = db.Database.BeginTransaction())
{
try
{
//由于本图书馆不允许一位读者同时有两本相同的书尚未归还，因此borrow唯一
Borrow borrow = db.Borrow.FirstOrDefault(br => br.BookId == book.Id && br.Reader.Id == reader.Id && br.ReturnTime == null);
borrow.ReturnTime = DateTime.Now;
borrow.Overdays = DateTime.Now.Day - borrow.DateShouldBeReturn.Day;
db.SaveChanges();
dbContextTransaction.Commit();
}
catch (Exception)
{
dbContextTransaction.Rollback();
}
}
}
}
//缴纳罚款业务
/*
* 根据Id找到数据库中对应的Fine数据行，修改其FinePrice
*/
public void ProcessPayFine(Reader reader, int Id)
{
using (var db = new 校园自助图书管理系统Entities())
{
using (var dbContextTransaction = db.Database.BeginTransaction())
{
try
{
Reader re = db.Reader.FirstOrDefault(r => r.Id == reader.Id);
Fine fine = db.Fine.FirstOrDefault(f => f.Id == Id);
Borrow br = db.Borrow.FirstOrDefault(b => b.FineId == Id);
re.Price -= fine.FinePrice;
fine.FinePrice = 0;
br.NeedtoFine = "已缴清";
db.SaveChanges();
dbContextTransaction.Commit();
}
catch (Exception)
{
dbContextTransaction.Rollback();
}
}
}
}