EntityFramework Core: Get changes occured in entity and related data

Based on this article (Entity Change Tracking using DbContext in Entity Framework 6), you should override SaveChanges() method to track entity changes and its related entities.

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

Actually, You should change the above code to the following sample:

public override int SaveChanges()
{
    var modifiedEntities = ChangeTracker.Entries()
        .Where(p => p.State == EntityState.Modified).ToList();
    var now = DateTime.UtcNow;

    foreach (var change in modifiedEntities)
    {
        var entityName = change.Entity.GetType().Name;
        var primaryKey = GetPrimaryKeyValue(change);

        foreach(var prop in change.OriginalValues.PropertyNames)
        {
            var originalValue = change.OriginalValues[prop].ToString();
            var currentValue = change.CurrentValues[prop].ToString();
            if (originalValue != currentValue) //Only create a log if the value changes
            {
                //Create the Change Log
            }
        }
    }
    return base.SaveChanges();
}