blocks|key|2732562|text|public+static+DbContext+GetDbContextFromEntity(object+entity)
{
++++var+object_context+=+GetObjectContextFromEntity(+entity+);

++++if+(+object_context+==+null+)
++++++++return+null;

++++return+new+DbContext(+object_context,+dbContextOwnsObjectContext:+false+);
}

private+static+ObjectContext+GetObjectContextFromEntity(object+entity)
{
++++var+field+=+entity.GetType().GetField("_entityWrapper");

++++if+(+field+==+null+)
++++++++return+null;

++++var+wrapper++=+field.GetValue(entity);
++++var+property+=+wrapper.GetType().GetProperty("Context");
++++var+context++=+(ObjectContext)property.GetValue(wrapper,+null);

++++return+context;
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|2732563|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>public static DbContext GetDbContextFromEntity(object entity)
{
 var object_context = GetObjectContextFromEntity( entity );

 if ( object_context == null )
 return null;

 return new DbContext( object_context, dbContextOwnsObjectContext: false );
}

private static ObjectContext GetObjectContextFromEntity(object entity)
{
 var field = entity.GetType().GetField("_entityWrapper");

 if ( field == null )
 return null;

 var wrapper = field.GetValue(entity);
 var property = wrapper.GetType().GetProperty("Context");
 var context = (ObjectContext)property.GetValue(wrapper, null);

 return context;
}
</code></pre>

blocks|key|150020|text|我找到another+way去找ObjectContext了。我不知道这样会不会更好。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|150021|public+static+ObjectContext+GetContext(this+IEntityWithRelationships+entity)
{
++if+(entity+==+null)
++++throw+new+ArgumentNullException("entity");

++var+relationshipManager+=+entity.RelationshipManager;
++var+relatedEnd+=+relationshipManager.GetAllRelatedEnds().FirstOrDefault();

++if+(relatedEnd+==+null)
++++throw+new+Exception("No+relationships+found");

++var+query+=+relatedEnd.CreateSourceQuery()+as+ObjectQuery;
++if+(query+==+null)
++++throw+new+Exception("The+Entity+is+Detached");

++return+query.Context;
}|code-block|syntax|javascript|150022|你可以像这样使用它：|150023|MyContext+context+=+myEntity.GetContext()+as+MyContext;|150024|entityMap|0|LINK|mutability|MUTABLE|url|http://blogs.msdn.com/b/alexj/archive/2009/06/08/tip-24-how-to-get-the-objectcontext-from-an-entity.aspx^0|3|B|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@$A|V|B|W|1|X]]|C|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|Z|8|@]|9|@]|C|$]]|$1|K|3|L|5|F|7|10|8|@]|9|@]|C|$G|H]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]]]

I found <a href="http://blogs.msdn.com/b/alexj/archive/2009/06/08/tip-24-how-to-get-the-objectcontext-from-an-entity.aspx" rel="noreferrer">another way</a> to get ObjectContext. Don't know if it's any better though.

<pre><code>public static ObjectContext GetContext(this IEntityWithRelationships entity)
{
 if (entity == null)
 throw new ArgumentNullException("entity");

 var relationshipManager = entity.RelationshipManager;
 var relatedEnd = relationshipManager.GetAllRelatedEnds().FirstOrDefault();

 if (relatedEnd == null)
 throw new Exception("No relationships found");

 var query = relatedEnd.CreateSourceQuery() as ObjectQuery;
 if (query == null)
 throw new Exception("The Entity is Detached");

 return query.Context;
}
</code></pre>

And you can use it like:

<pre><code>MyContext context = myEntity.GetContext() as MyContext;
</code></pre>

blocks|key|2732621|text|对于EF6，我稍微修改了一下德克的回答：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2732622|++++public+static+DbContext+GetDbContextFromEntity(object+entity)
++++{
++++++++var+object_context+=+GetObjectContextFromEntity(entity);

++++++++if+(object_context+==+null+%7C%7C+object_context.TransactionHandler+==+null)
++++++++++++return+null;

++++++++return++object_context.TransactionHandler.DbContext;
++++}

++++private+static+ObjectContext+GetObjectContextFromEntity(object+entity)
++++{
++++++++var+field+=+entity.GetType().GetField("_entityWrapper");

++++++++if+(field+==+null)
++++++++++++return+null;

++++++++var+wrapper+=+field.GetValue(entity);
++++++++var+property+=+wrapper.GetType().GetProperty("Context");
++++++++var+context+=+(ObjectContext)property.GetValue(wrapper,+null);

++++++++return+context;
++++}|code-block|syntax|javascript|2732623|没有新的DbContext()，并且它是可转换到您的主要实体类中的。|2732624|注意:对于上面返回值为空的问题，如果实体没有保存/提交，就会发生这种情况。只能在.Local中找到的新实体似乎没有"_entityWrapper“字段。|2732625|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|P|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

For EF6, I modified Dirk's answer slightly:

<pre><code> public static DbContext GetDbContextFromEntity(object entity)
 {
 var object_context = GetObjectContextFromEntity(entity);

 if (object_context == null || object_context.TransactionHandler == null)
 return null;

 return object_context.TransactionHandler.DbContext;
 }

 private static ObjectContext GetObjectContextFromEntity(object entity)
 {
 var field = entity.GetType().GetField("_entityWrapper");

 if (field == null)
 return null;

 var wrapper = field.GetValue(entity);
 var property = wrapper.GetType().GetProperty("Context");
 var context = (ObjectContext)property.GetValue(wrapper, null);

 return context;
 }
</code></pre>

No new DbContext() and it's castable into your main Entities class.

Note: To the above question of null return value, this will happen if the entity has not been saved/committed. New entities that can only be found in .Local do not seem to have the "_entityWrapper" field.

I'm deep somewhere in the Business layer in a debugging session in Visual Studio trying to figure out why an Entity is behaving strangely when trying to persist the changes.

It would really be helpful to get a reference to the DbContext this Entity belongs to, at this point in the call stack.

I.e. to see what the state is of this Entity is (Unchanged, Modified, etc).

So I'm looking for a helper method like this:

<pre><code>var db_context = DbContextHelpers.GetDbContext(entity);

// after that I could do something like this
var state = db_context.Entry(entity);
</code></pre>

I can use this stuff in the Immediate window during debugging.

Anyone any suggestions?

Extra notes

The Entity must be aware of the <code>DbContext</code> somewhere, because it is using it for lazy loading navigation properties?

Get DbContext from Entity in Entity Framework

Visual Studio

我在业务层的某处，在Visual Studio的调试会话中，试图弄清楚为什么实体在试图持久存储更改时行为异常。在调用堆栈中的这一点上，获得此实体所属的DbContext的引用将非常有帮助。即查看该实体的状态是什么(未改变、修改等)。所以我正在寻找一个像这样的辅助方法：var db_context = DbContext...

问从实体框架中的实体获取DbContext
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