public static void 消除EF追踪()
{
using (var db = new DonatorsContext())
{
Console.WriteLine("默认情况下，实体的状态");
var provinceNormal = db.Provinces.Include(p => p.Donators);
foreach (var province in provinceNormal)
{
FluentConsole.Green.Line("省份追踪状态：{0}", db.Entry(province).State);
foreach (var donator in province.Donators)
{
Console.WriteLine("打赏者的追踪状态：{0}", db.Entry(donator).State);
}
}
Console.WriteLine("使用AsNoTracking()方法后，实体的状态");
var provinceNoTracking = db.Provinces.Include(p => p.Donators).AsNoTracking();
//使用AsNoTracking()方法设置不再追踪实体
foreach (var province in provinceNoTracking)
{
FluentConsole.Green.Line("省份追踪状态：{0}", db.Entry(province).State);
foreach (var donator in province.Donators)
{
Console.WriteLine("打赏者的追踪状态：{0}", db.Entry(donator).State);
}
}
}
Console.WriteLine("EF中实体的状态比较。");
}
//设置实体状态删除
public static void 设置实体状态删除()
{
//通过设置实体状态删除
var toDeleteProvince = new Province {
Id = 1
};
toDeleteProvince.Donators.Add(new Donator
{
Id = 2
});
toDeleteProvince.Donators.Add(new Donator
{
Id = 3
});
toDeleteProvince.Donators.Add(new Donator
{
Id = 4
});
using (var db = new DonatorsContext())
{
PrintAllDonators(db); //删除前先输出现有的数据,不能写在下面的using语句中，否则Attach方法会报错，原因我相信你已经可以思考出来了
}
using (var db = new DonatorsContext())
{
db.Provinces.Attach(toDeleteProvince);
foreach (var donator in toDeleteProvince.Donators.ToList())
{
db.Entry(donator).State = EntityState.Deleted;
}
db.Entry(toDeleteProvince).State = EntityState.Deleted; //删除子实体再删除父实体。
db.SaveChanges();
Console.WriteLine("删除之后的数据如下：\r\n");
PrintAllDonators(db);
}
}
//Web应用，更新Province
public static void Web应用UpdateProvince()
{
var province = new Province {
Id = 2, ProvinceName = "山东省更新"
};
province.Donators.Add(new Donator
{
Name = "醉、千秋", //再改回来
Id = 4,
Amount = 12m,
DonateDate = DateTime.Parse("2015-7-12")
});
using (var db = new DonatorsContext())
{
db.Entry(province).State = EntityState.Modified;
foreach (var donator in province.Donators)
{
db.Entry(donator).State = EntityState.Modified;
}
db.SaveChanges();
}
Console.WriteLine("Web应用更新Province");
}
//Insert Province ,修改实体的状态为added
public static void InsertProvince2()
{
var province = new Province {
ProvinceName = "广东省"
};
province.Donators.Add(new Donator
{
Name = "求余",
Amount = 30,
DonateDate = DateTime.Parse("2016-7-12")
});
using (var db = new DonatorsContext())
{
db.Entry(province).State = EntityState.Added;
db.SaveChanges();
}
Console.WriteLine("InsertProvince,修改实体的状态为added");
}