Using ChangeTracker with EntityState.Modified-CodePudding

Given the following function the variable currentModel is already the modified model that I want to update and it might have some properties different from the ones in the database and this function correctly updates the modified values.

Now I want to track the changes made before the update, the problem is that the ChangeTracker is detecting all properties as modified even when only one is acctualy different from the original model.

Is there a way to use ChangeTracker while also updating the statement with EntityState.Modified

Related links:

DbEntityEntry.GetDatabaseValues Method

DbPropertyValues.SetValues Method

ChangeTracker.Clear Method

CodePudding user response：

It is possible to copy the entity's values from a other class instance as follows :

public void SaveCustomer(Client currentModel)
{
    var objFromDbAct = _db.Clients.Local.FirstOrDefault(c => c.Recid == currentModel.Recid);
    if (objFromDbAct == null)
    {
        _db.Update(currentModel);
    }
    else
    {
        var preEntity = _db.Entry(objFromDbAct);
        preEntity.CurrentValues.SetValues(currentModel);
    }

    _db.ChangeTracker.DetectChanges();
    string trackChanges = _db.ChangeTracker.DebugView.LongView;

    _db.SaveChanges();
}

trackChanges value :

Client {Recid: 1} Modified
  Recid: 1 PK
  Addr1: 'Address 1'
  Addr2: 'Address 2'
  Zip: 'Modified' Modified Originally 'Zip'

And the SQL executed by SaveChanges:

UPDATE [Clients] SET [Zip] = @p0
WHERE [Recid] = @p1;