实体框架5：正确的方法，以取代在上下文中的条目 [英] Entity Framework 5 : Proper method to replace entry in context

问题描述

我想要做的是简单的。 我有部分在DB的名单，我想删除/插入/更新它们根据更新列表。

主要的问题是，当我想更换一个条目我不能将其连接到上​​下文，因为旧的（待更新）项已连接（由previous读取调用）和一个例外是抛出。

我来到身边有3个想法。

1. 手动拆下旧条目并附加了新的（虽然改变实体状态到分离仍抛出异常）
2. 手动用新的改变旧项的值
3. 请读调用非轨道能（AsNoTracking（）），这似乎做工精细，但我担心对lazyloading影响。

有没有想任何功能context.entry.replace（oldEntry，newEntry）或其他任何适当的方式做到这一点？

 的IEnumerable＆LT; SoldPart＆GT;老= db.SoldParts.Where（SP =＆GT; sp.sessionId ==的sessionId）;

                VAR toDelete = old.Where（PO =＆GT;！parts.Any（PU =＆GT; pu.id == po.id））;
                VAR toCreate = parts.Where（PO =＆GT;！old.Any（PU =＆GT; pu.id == po.id））;
                VAR更新所使用= parts.Where（PO =＆GT; old.Any（PU =＆GT; pu.id == po.id））;


                的foreach（在toDelete SoldPart项）
                {
                    db.SoldParts.Attach（项目）;
                    db.SoldParts.Remove（项目）;
                }
                的foreach（在toCreate SoldPart项）
                {
                    db.SoldParts.Add（项目）;
                }

                的foreach（在更新所SoldPart项）
                {

                    db.SoldParts.Attach（项目）;
                    db.Entry（项目）.State = EntityState.Modified;
                }


                db.SaveChanges（）;
 

解决方案

有自动的方式来更新由独立一头连着实体的值，但它仅适用于标/复杂性。没有导航属性：

  deb.Entry（oldEntry）.CurrentValues​​.SetValues​​（newEntry）;
 

What i want to do is simple. I have a list of parts in the db, and i want to delete/insert/update them according to an update list.

The main issue is that, when i want to replace an entry i can't attach it to the context because the older(to be updated) entry is already attached (by previous read call) and an exception is thrown.

I came around with 3 thoughts.

1. Manually Detach the old entry and attach the new one (although changing entity state to detached still throws exception)
2. Manually change the values of the old entry with the new ones
3. Make the read call non track able (AsNoTracking()), this seems to work fine but i am concerned about impact on lazyloading.

Is there any functionality like "context.entry.replace(oldEntry,newEntry)" or any other proper way to do this?

IEnumerable<SoldPart> old = db.SoldParts.Where(sp=>sp.sessionId == sessionId);

                var toDelete = old.Where(po=> !parts.Any(pu=>pu.id == po.id));
                var toCreate = parts.Where(po => !old.Any(pu => pu.id == po.id));
                var toUpdate = parts.Where(po => old.Any(pu => pu.id == po.id));


                foreach (SoldPart item in toDelete)
                {
                    db.SoldParts.Attach(item);
                    db.SoldParts.Remove(item);
                }
                foreach (SoldPart item in toCreate)
                {
                    db.SoldParts.Add(item);
                }

                foreach (SoldPart item in toUpdate)
                {

                    db.SoldParts.Attach(item);
                    db.Entry(item).State = EntityState.Modified;
                }


                db.SaveChanges();

解决方案

There is automatic way to update attached entity's values from detached one but it works only on scalar / complex properties. Not on navigation properties:

deb.Entry(oldEntry).CurrentValues.SetValues(newEntry);

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