Entity Framework 7 SaveChanges

问题

Is there any way to register a callback that will be called before a model in EF7 is saved to the database? What I want to do is to set a ModifiedBy and ModifiedDate property that I have on all models. I'm not that keen to do this manually before each save so I'm looking for some more generic and automatic way.

回答1:

ChangeTracker.Entries() allows you to get all of the entity changes. You could override SaveChanges in your DbContext and set the modified properties using something like the following code.

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

public override async Task<int> SaveChangesAsync( CancellationToken cancellationToken = new CancellationToken() )
{
    SetModifiedInformation();
    return await base.SaveChangesAsync( cancellationToken );
}

private void SetModifiedInformation()
{
    foreach (var entityEntry in ChangeTracker.Entries())
    {
        var entity = entityEntry.Entity as ChangeTracking;
        if (entity != null)
        {
            entity.ModifiedBy = "Get User Here";
            entity.ModifiedTime = DateTime.Now;
        }
    }
}

来源：https://stackoverflow.com/questions/34951613/entity-framework-7-savechanges