blocks|key|1747408|text|我知道这篇文章很老了，但这可能会帮助下一个到达的人通过谷歌搜索"Entitiy“和"Identity”听到。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1747409|看起来实体框架确实尊重服务器生成的主键，就像设置了"Identity“属性时的情况一样。但是，应用程序端模型仍然需要在CreateYourEntityHere方法中提供主键。在对上下文进行SaveChanges()调用时，将丢弃此处指定的键。|offset|length|style|CODE|1747410|页面here提供了有关这方面的详细信息。|1747411|entityMap|0|LINK|mutability|MUTABLE|url|https://blogs.msdn.microsoft.com/dsimmons/2008/08/10/entity-services-metadata-mapping/#Section_17^0|0|1N|K|2M|D|0|2|4|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|S|8|@$D|T|E|U|F|G]|$D|V|E|W|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|X|8|@]|9|@$D|Y|E|Z|1|10]]|A|$]]|$1|J|3|-4|5|6|7|11|8|@]|9|@]|A|$]]]|K|$L|$5|M|N|O|A|$P|Q]]]]

I know this post is quite old, but this may help the next person arriving hear via a Google search for "Entitiy Framework" and "Identity".

It seems that Entity Frameworks does respect server-generated primary keys, as the case would be if the "Identity" property is set. However, the application side model still requires a primary key to be supplied in the <code>CreateYourEntityHere</code> method. The key specified here is discarded upon the <code>SaveChanges()</code> call to the context.

The page <a href="https://blogs.msdn.microsoft.com/dsimmons/2008/08/10/entity-services-metadata-mapping/#Section_17" rel="nofollow noreferrer">here</a> gives the detailed information regarding this.

blocks|key|1532918|text|如果您使用的是Entity+Framework5，则可以使用以下属性。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1532919|[DatabaseGenerated(DatabaseGeneratedOption.Identity)]|code-block|syntax|javascript|1532920|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

If you are using Entity Framework 5, you can use the following attribute.

<pre><code>[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
</code></pre>

blocks|key|1747258|text|您应该设置标识列的标识规范，以便将(Is+Identity)属性设置为true。您可以在SSMS中的表设计器中执行此操作。然后您可能需要更新实体数据模型。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1747259|也许这就是您所说的“主键是标识列”的意思，或者您可能错过了这一步。|1747260|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

You should set the identity columns' identity specification so that the (Is Identity) property is set to true. You can do this in your table designer in SSMS. Then you may need to update the entity data model.

Perhaps that what you mean by saying the "Primary key is an identity column," or perhaps you missed this step.

blocks|key|1532678|text|这是我见过的最好的答案。您必须手动编辑存储层xml，以便在每个默认值设置为NewID()的UniqueIdentifier类型的主键上设置StoreGeneratedPattern="Identity"。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1532679|http://web.archive.org/web/20130728225149/http://leedumond.com/blog/using-a-guid-as-an-entitykey-in-entity-framework-4/|1532680|entityMap|0|LINK|mutability|MUTABLE|url^0|11|7|19|G|1X|W|0|0|3B|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]|$9|T|A|U|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|V|8|@]|D|@$9|W|A|X|1|Y]]|E|$]]|$1|H|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|I|$J|$5|K|L|M|E|$N|G]]]]

This is the best answer I've seen. You have to manually edit the storage layer xml to set <code>StoreGeneratedPattern="Identity"</code> on each primary key of type <code>UniqueIdentifier</code> that has the default value set to <code>NewID()</code>.

<a href="http://web.archive.org/web/20130728225149/http://leedumond.com/blog/using-a-guid-as-an-entitykey-in-entity-framework-4/" rel="nofollow">http://web.archive.org/web/20130728225149/http://leedumond.com/blog/using-a-guid-as-an-entitykey-in-entity-framework-4/</a>

blocks|key|1747174|text|Entity+Framework知道并且可以处理标识列。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1747175|你的问题可能不是EF本身，而是生成的表单视图。尝试从插入表单中删除identity列的输入，让我们看看会发生什么。|1747176|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

Entity Framework is aware and can handle identity columns.

Your problem can be maybe not the EF itself but the generated formview of it. Try to delete the input for the identity column from the insert form and let's see what happens.

blocks|key|1532362|text|如果在拔掉头发之前所有这些都失败了-尝试删除您的EntityModel并从SQL+Server重新导入。如果你一直在调整键和关系，并依赖于“从数据库更新模型”功能，那么在我发现的RC版本中，它仍然有一些bit+-一个新的导入可能会有所帮助。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1532363|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

If all else fails before you rip out your hair - try deleting your EntityModel and re-importing from SQL Server. If you've been tweaking the keys and relationships and relying on the 'update model from database' function it's still a bit buggy in the RC version I've found - a fresh import may help.

blocks|key|1532854|text|在C#中，您可以这样做来让它意识到：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1532855|在你的FooConfiguration.cs+:+EntityTypeConfiguration<Foo>中|offset|length|style|CODE|1532856|this.Property(x+=>+x.foo).HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);|code-block|syntax|javascript|1532857|然后，要使用它，只需确保将该项插入到上下文中，并在使用x.foo之前调用context.SaveChanges()来获取更新后的自动递增值。否则，x.foo将仅为0或null。|1532858|entityMap^0|0|3|1E|0|0|R|5|10|L|21|5|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@$D|S|E|T|F|G]]|9|@]|A|$]]|$1|H|3|I|5|J|7|U|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|V|8|@$D|W|E|X|F|G]|$D|Y|E|Z|F|G]|$D|10|E|11|F|G]]|9|@]|A|$]]|$1|O|3|-4|5|6|7|12|8|@]|9|@]|A|$]]]|P|$]]

In C# you can do something like this to make it aware:

In your <code>FooConfiguration.cs : EntityTypeConfiguration&lt;Foo&gt;</code>:

<pre class="lang-cs prettyprint-override"><code>this.Property(x =&gt; x.foo).HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
</code></pre>

Then to use it, just be sure to insert the item into the context and call <code>context.SaveChanges()</code> before using <code>x.foo</code> to get the updated auto-incremented value. Otherwise <code>x.foo</code> will just be 0 or null.

blocks|key|1532544|text|由于某些原因，实体框架不能完全理解身份。正确的解决方法是将该列的Setter设置为Private。这将使任何生成的UI理解它不应该设置identity值，因为它不可能设置私有字段。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1532545|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Entity framework does not fully understand Identities for some reason. The correct workaround is to set the Setter for that column to Private. This will make any generated UI understand that it should not set the identity value since it is impossible for it to set a private field.

blocks|key|1532626|text|对我来说起作用的是将StoreGeneratedPattern设置为None，而它是一个标识列。现在，所有的工作都是一致的。这样做的主要问题是，如果您有许多模型，那么编辑模型是一项非常繁琐的工作。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1532627|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

What worked for me was setting the StoreGeneratedPattern to None, when it was an Identity column. Now it all works consistently. The main problem with this is editing the models is an extreme chore if you have many models.

blocks|key|1747754|text|我真不敢相信。智能感知ItemCollection在SaveChanges之后生成ID+=0的单个项目。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1747755|++++++++++++Dim+ItemCollection+=+From+d+In+action.Parameter
++++++++++++Select+New+STOCK_TYPE+With+{
++++++++++++++++++++++++.Code+=+d.ParamValue.<Code>.Value,
++++++++++++++++++++++++.GeneralUseID+=+d.ParamValue.<GeneralUse>.Value,
++++++++++++}


++++++++++++GtexCtx.STOCK_TYPE.AddObject(+ItemCollection.FirstOrDefault)
++++++++++++GtexCtx.SaveChanges()|code-block|syntax|javascript|1747756|不管我做什么。经过8个小时，包括删除我的模型，35次构建和重建，实验和编辑EDMX的XML，现在几乎到删除我的整个SQL+Server数据库。在第36次编译时，这个令人难以置信的解决方案起作用了|1747757|++++++++++++Dim+abc+=+ItemCollection.FirstOrDefault
++++++++++++GtexCtx.STOCK_TYPE.AddObject(abc)
++++++++++++GtexCtx.SaveChanges()|1747758|abc.ID+yield+41+(我需要的身份)|1747759|编辑:这里有一个简单的代码，用来思考循环AddObject和仍然获得ID|1747760|Dim+listOfST+As+List(Of+STOCK_TYPE)+=+ItemCollection.ToList()
++++++For+Each+q+As+STOCK_TYPE+In+listOfST+
+++++++++GtexCtx.STOCK_TYPE.AddObject(q)
++++++Next
+GtexCtx.SaveChanges()

...more+code+for+inter-relationship+tables|1747761|在SaveChanges之后尝试Intellisence，你会发现更新的ID。|1747762|entityMap^0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|W|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|Y|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|Z|8|@]|9|@]|A|$]]|$1|O|3|P|5|D|7|10|8|@]|9|@]|A|$E|F]]|$1|Q|3|R|5|6|7|11|8|@]|9|@]|A|$]]|$1|S|3|-4|5|6|7|12|8|@]|9|@]|A|$]]]|T|$]]

I cannot believe it. Intellisensing ItemCollection yield the single item with ID = 0 after SaveChanges.

<pre><code> Dim ItemCollection = From d In action.Parameter
 Select New STOCK_TYPE With {
 .Code = d.ParamValue.&lt;Code&gt;.Value,
 .GeneralUseID = d.ParamValue.&lt;GeneralUse&gt;.Value,
 }


 GtexCtx.STOCK_TYPE.AddObject( ItemCollection.FirstOrDefault)
 GtexCtx.SaveChanges()
</code></pre>

No matter what I do. After 8 hours including deleting my model, 35 times building and rebuilding, experimenting and editing the XML of EDMX and now almost coming to deleting my whole SQL Server database. At the 36th compile, this dumbfounding solution worked

<pre><code> Dim abc = ItemCollection.FirstOrDefault
 GtexCtx.STOCK_TYPE.AddObject(abc)
 GtexCtx.SaveChanges()
</code></pre>

abc.ID yield 41 (the identity i needed)

EDIT: Here's a simple code for thought for looping AddObject and still get ID

<pre><code>Dim listOfST As List(Of STOCK_TYPE) = ItemCollection.ToList()
 For Each q As STOCK_TYPE In listOfST 
 GtexCtx.STOCK_TYPE.AddObject(q)
 Next
 GtexCtx.SaveChanges()

...more code for inter-relationship tables
</code></pre>

Try Intellisence listOfST after SaveChanges and you will find updated ID. Maybe there's better way but the concept is there

Is the Entity Framework aware of identity columns? 

I am using SQL Server 2005 Express Edition and have several tables where the primary key is an identity column. when I use these tables to create an entity model and use the model in conjunction with an entity datasource bond to a formview in order to create a new entity I am asked to enter a value for the identity column. Is there a way to make the framework not ask for values for identity columns?

ADO.NET Entity Framework and identity columns

实体框架是否知道identity列？我使用的是SQL Server2005Express Edition，并且有几个主键是标识列的表。当我使用这些表创建实体模型，并将该模型与实体数据源绑定到formview以创建新实体时，系统会要求我为identity列输入值。有没有一种方法可以使框架不要求标识列的值？

问ADO.NET实体框架和标识列
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