//[TestMethod]
public void TestAttach()
{
LinkMethod lm = null;
using (MyDBExt db = new MyDBExt())
{
lm = db.LinkMethods.Include(p=>p.user).FirstOrDefault();
}
User user = null;
using (MyDBExt db = new MyDBExt())
{
user = db.Users.FirstOrDefault(u => !u.Code.Equals(lm.user.ID));
}
lm.MethodType = "B";
lm.user = user;
using (MyDBExt db = new MyDBExt())
{
// 附加到新上下文
// 方法一
//db.Entry(lm).State = System.Data.EntityState.Modified;
//db.Entry<User>(lm.user).State = System.Data.EntityState.Modified;
db.LinkMethods.Add(lm); // lm.user的状态也是Added,如果不把lm.user的状态设置为Unchanged，就会出现主键重复的错误
db.Entry<LinkMethod>(lm).State = System.Data.EntityState.Modified;
//db.Entry<User>(lm.user).State = System.Data.EntityState.Unchanged;
DbReferenceEntry dre = db.Entry<LinkMethod>(lm).Reference(l => l.user);
bool x = dre.IsLoaded;
User u = lm.user;
x = dre.IsLoaded;
DbEntityEntry<LinkMethod> dee = db.Entry<LinkMethod>(lm);
DbPropertyEntry dpe = dee.Property(l => l.MethodType);
//db.LinkMethods.Attach(lm);
//lm.user = user;
db.SaveChanges();
}
using (MyDBExt db = new MyDBExt())
{
IQueryable s = db.Users.Select(u => new { u, xX = db.LinkMethods.Where(l => l.user.ID.Equals(u.ID)).Count()}); // OK
//IQueryable s = db.Users.Select(u => new { u, xX = db.LinkMethods.Where(l => l.user.ID.Equals(u.ID)).Select(l => l.MethodType) }); //NO
//IQueryable s = db.Users.Select(u => new { u, xX = "ddddddddddddd" }); //OK
}
}
public void TestMethod1()
{
using (MyDBExt db = new MyDBExt())
{
//db.Configuration.LazyLoadingEnabled = true;
//DbSet<LinkMethod> lmss = db.Set<LinkMethod>();
//lmss.Create();
//IQueryable<LinkMethod> lmsOld = ext.Set(typeof(LinkMethod));
// 错误信息：实体类型LinkMethod不是当前上下文db的模型的一部分
Expression<Func<LinkMethod,LinkMethod>> d2 = p => p;
IQueryable<LinkMethod> lmsOld = db.LinkMethods.Select(d2);
// 单向关联，反向查询
// p.LinkMethods 等价于 db.LinkMethods.Where(l => l.user.ID.Equals(p.ID)) 或者 db.LinkMethods.Where(l => l.user == p)
//IQueryable<User> test = db.Users.Where(p => db.LinkMethods.Where(l => l.user == p).Count() > 0);
IQueryable test = db.Users.Select(p => db.LinkMethods.Where(l => l.user == p).Select(l => l) );
IQueryable test1 = db.Users.Select(p =>new {p.Name,p.Code, p.Roles });
//IQueryable<User> test = db.Users.Where(p => p.LinkMethods(db).Where(l => l.user == p).Count() > 0);
//IQueryable test = db.Users.Select(p => p.Roles);
//IQueryable<LinkMethod> lmsOld = lmss.Select(p => p);
foreach (LinkMethod lm in lmsOld)
{
db.LinkMethods.Remove(lm);
//db.Set<LinkMethod>().Remove(lm);
}
//ext.SaveChanges();
User userOld = db.Users.FirstOrDefault(p => p.Code.Equals("xiongxiong"));
if (userOld != null)
{
db.Users.Remove(db.Users.FirstOrDefault(p => p.Code.Equals("xiongxiong")));
}
User u = new User();
u.ID = Guid.NewGuid().ToString();
u.Code = "xiongxiong";
u.Name = "雄";
u.Password = "******";
db.Users.Add(u);
LinkMethod lm1 = new LinkMethod();
lm1.ID = Guid.NewGuid().ToString();
lm1.MethodType = "A";
lm1.Content = "content";
lm1.user = u;
db.LinkMethods.Add(lm1);
//db.Set<LinkMethod>().Add(lm1);
db.SaveChanges();
IQueryable<LinkMethod> lms = db.Set<LinkMethod>().Select(p => p);
//IQueryable<User> users = ext.Users.Select(p => p);
//ICollection<LinkMethod> lms1 = users.Select(p => p.getLinkMethodsByUser());
}
}
public static IQueryable<LinkMethod> LinkMethods(this User u, MyDBExt db)
{
return db.LinkMethods.Where(l => l.user.ID.Equals(u.ID));
}