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How to work with modified entity data

At the moment, in order to check for changes in the entity framework object, I check the database and I go through each object and compare the properties with the updated one if they are updated and also the updated date will change.

I find it very long in code and was wondering if there is a cleaner way to validate changes with an entity. I thought maybe using deepcopy with a comparison object and compare something like below. But I would have to set each of my tables to serialize and I don't know if that is good.

if (Equals(oldentity, newentity))
{
    newentity.ModifiedDate = DateTime.Now
}

My current way of tracking changes

if (oldentity.firstname != newentity.firstname || oldentity.lastname != newentity.lastname)
{
    newentity.ModifiedDate = DateTime.Now
}

The if statement is a fragment, my object has many properties, so it gets long ...

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3 answers


You can provide your organization with an interface with CreatedDate

and ModifiedDate

properties:

public interface ITrackedEntity
{
    DateTime CreatedDate    { get; set; }
    DateTime ModifiedDate   { get; set; }
}

Then override SaveChanges

and SaveChangesAsync

in DBContext

to handle properties for added and modified objects automatically:



public override int SaveChanges()
{
    this.UpdateTrackedEntities();
    return base.SaveChanges();
}

public override async Task<int> SaveChangesAsync()
{
    this.UpdateTrackedEntities();
    return await base.SaveChangesAsync();
}

private void UpdateTrackedEntities()
{
    var entities = ChangeTracker.Entries().Where(x => x.Entity is ITrackedEntity && (x.State == EntityState.Added || x.State == EntityState.Modified));

    foreach (var entity in entities)
    {
        if (entity.State == EntityState.Added)
        {
            ((ITrackedEntity)entity.Entity).CreatedDate = DateTime.UtcNow;
        }

        ((ITrackedEntity)entity.Entity).ModifiedDate = DateTime.UtcNow;
    }
}

Makes things a lot easier.

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You can try something like



public bool HasUnsavedChanges(MyObject oldentity)
{
    return (YourObjectContext.ObjectStateManager.GetObjectStateEntries(EntityState.Modified).Any(x=>x.Id == oldentity.Id));
}
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Entity Framework has ChangeTracker in DbContext.

I, for example, override my SaveChanges () context and it can get all the changes made to my entities.

public override int SaveChanges()
{
    ChangeTracker.DetectChanges();
    var addedEntities = ChangeTracker.Entries().Where(x => x.State == EntityState.Added).ToList();
    var modifiedEntities = ChangeTracker.Entries().Where(x => x.State == EntityState.Modified).ToList();
    var deletedEntities = ChangeTracker.Entries().Where(x => x.State == EntityState.Deleted).ToList();

    //Save info generating the ids
    var ret = base.SaveChanges();

    //Generate Logs logic
    ...

    return ret;
}

ChangeTracker also takes an object as a parameter if you only want to check one object for changes.

More information on ChangeTracker ( https://msdn.microsoft.com/en-us/library/system.data.entity.infrastructure.dbchangetracker(v=vs.113).aspx )

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