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Editorial Team
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Asked: 2026-06-05T19:39:13+00:00

If an entities properties have changed in a controller action and Update/SaveChanges is not

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If an entities properties have changed in a controller action and Update/SaveChanges is not called, will that entity be updated automatically?

I am using EF 4.1 with a repository pattern. I handle all CRUD operations in my EfRepository class like this:

public void Update(T entity)
{
  try{_context.SaveChanges();}
  catch{//do stuff}
}

//etc.

In my application I have an ajax/ActionResult call that gets an entity from the db, performs some basic calculations, and returns a JSON object. To make a long story short I discovered a bug in a static helper I was using in my ActionResult that was changing a property value on my entity and not the JSON-model I was returning.

My action method has no Update methods yet my entity was being updated every time I called this action. Using Sql Profiler I confirmed an update statement that was tailored to update my entity and the one(1) property my buggy static method was changing.

I placed a break point at my Update method in my repository class and even though my entity was being updated by EF, MY Update method was never called. The summary for the interface method ‘Find’ (which is what I use) in IDbSet says,

Finds an entity with the given primary key values. If an entity with
the given primary key values exists in the context, then it is
returned immediately without making a request to the store. Otherwise,
a request is made to the store for an entity with the given primary
key values and this entity, if found, is attached to the context and
returned. If no entity is found in the context or the store, then null
is returned.

There are some real good example here as well.

I think given my entity was attached, the short answer to my question is ‘YES’. But being somewhat new to EF I found this to be a very difficult bug to figure out as it still appears there some things going on under the covers that I could not track down. I hesitated in posting this as a question but thought someone more knowledgeable could expand on my assumed answer of YES and at the bare minimum help someone else who runs across this.

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1 Answer

  1. Editorial Team

    If an entities properties have changed in a controller action and
    Update/SaveChanges is not called, will that entity be updated
    automatically?

    No, ef will only propagate your changes to the database on a SaveChanges call. Save only happens manually (IE you have to explicitly call SaveChanges).

    What is really important to understand though is that SaveChanges saves all current modifications to the context. This means if you are sharing a context your changes will be saved when anyone (not just you) calls SaveChanges.

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