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    <p>Thanks to @Ladislav for getting me in the right direction. Here's the code for a generic <code>Exists()</code> method.</p> <p>I'd like to note that this doesn't require reflection and seems to perform quite well. The only thing I'm not thrilled about is that <code>TryGetObjectByKey()</code> has the side-effect of attaching the found entity. Since I don't want <code>Exists()</code> to have that unintentional result I have to detach the entity if it was found.</p> <pre><code>public Boolean Exists(T entity) { var objContext = ((IObjectContextAdapter)this.DbContext).ObjectContext; var objSet = objContext.CreateObjectSet&lt;T&gt;(); var entityKey = objContext.CreateEntityKey(objSet.EntitySet.Name, entity); Object foundEntity; var exists = objContext.TryGetObjectByKey(entityKey, out foundEntity); // TryGetObjectByKey attaches a found entity // Detach it here to prevent side-effects if (exists) { objContext.Detach(foundEntity); } return (exists); } </code></pre>
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    1. POGeneric Way to Check If Entity Exists In Entity Framework?
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    1. COBut `Attach` and `SaveChanges` won't save any changes because attaching leaves the entity in state `Unchanged`. You must set the state to `Modified` after `Attach`. But this is ineffective since all columns will be updated no matter if they really did change. To avoid this you have to load the original into the context and apply the changes on property level. But then you don't need `Exists` since it would only cause to load the entity twice. And what will you do when `entity` has navigation properties and related objects have to be updated or not? I have doubt in a generic `Save` approach.
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    2. CO@Yuck: I'm only talking about the "if"-case, not the "else"-case of course. I don't see how this could save anything, it even won't issue any SQL command to the database. Quote from here: http://blogs.msdn.com/b/adonet/archive/2011/01/29/using-dbcontext-in-ef-feature-ctp5-part-4-add-attach-and-entity-states.aspx **...Note that no changes will be made to the database if SaveChanges is called without doing any other manipulation of the attached entity. This is because the entity is in the Unchanged state...** And I can confirm this from my own tests.
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    3. CO@Yuck: No, that's wrong. It doesn't update. If you have a `User` in the database with `Id` = 1 and `Name` = "Paul" and then *attach* a `User` entity with `Id` = 1 and `Name` = "Mary" to the context and then directly call `SaveChanges`, the `User` with `Id` = 1 in the database still has the name "Paul". (I'm talking about EF 4.1 too, but it doesn't matter, this behaviour is EF core stuff.)
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