CODEWITHSUNDEEP
c#entity-framework-coreaudit-logging
Wpowell
Wpowell

Reputation: 31

EF Core ChangeTracker() current and original values are the same for Modified entities

I'm creating an audit trail using EF Core's change tracker, and for every entity that has the state Added, Modified or Deleted, I create a new audit entity to insert into my Audit table. I want to take a snapshot of what I had before an UPDATE and capture it in JSON and do the same for a snapshot of the entity after the UPDATE.

var entityType = this.Model.FindEntityType(dbEntry.Entity.GetType());
var originalObjectProperties = new Dictionary<string, object>();
var currentObjectProperties = new Dictionary<string, object>();

foreach (var property in entityType.GetProperties())
{
    originalObjectProperties.Add(property.GetColumnName().ToUpper(), dbEntry.OriginalValues[property.Name]);
    currentObjectProperties.Add(property.GetColumnName().ToUpper(), dbEntry.CurrentValues[property.Name]);
}

dbEntry is the entity entry from the change tracker. These give me the same exact JSON though. In my tests I have an INSERT, UPDATE and DELETE, and this is what ends up in my BEFORE_JSON and AFTER_JSON in my database for my UPDATE:

{
    "WORK_REQUEST_KEY": 2,
    "PROJECT_NAME": "This has now been updated",
    "WR_TYPE_KEY": 2
}
{
    "WORK_REQUEST_KEY": 2,
    "PROJECT_NAME": "This has now been updated",
    "WR_TYPE_KEY": 2
}

Upvotes: 3

Views: 2140

Answers (1)

Jeremy Lakeman
Jeremy Lakeman

Reputation: 11120

I think this should be equivalent, but with slightly less complexity;

var originalObjectProperties = new Dictionary<string, object>();
var currentObjectProperties = new Dictionary<string, object>();

foreach (var property in dbEntry.Properties)
{
    var key = property.Metadata.GetColumnName().ToUpper();
    originalObjectProperties.Add(key, property.OriginalValue);
    currentObjectProperties.Add(key, dbEntry.CurrentValues[property.Metadata]);
}

But what you get out of your change tracker, depends on what you put into it. Were your entities loaded from the database and then changed? Or re-attached as modified?

The most reliable way to audit original values would be in a database trigger, or perhaps using some other built-in database feature.

Upvotes: 2

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