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

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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
}
audit-logging entity-framework-core c#
1 Answers

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.

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