Question

I have an ASP.NET MVC3 web application with UI, Business (entities), and Data (DbContext) layers. I am using Entity Framework 4.1 Code First. Right now, I am overriding the DbContext.SaveChanges() in the Data layer so that I can set the ModifiedDate for all changes made to any entity objects that implement my IAuditable interface. I have a static DateProvider class and method (GetCurrentDate) that returns DateTime.Now (unless I’m running a test, in which case, it returns whatever I told it to).

I would like to automatically set the ModifiedBy property to the current user as well. What is the best way to go about doing this? Is there something that is built in the framework that will allow me to access this information or do I need to set something up kind of like the DateProvider class? This is an Active Directory environment and we use WindowsAuthentication in IIS.

Here is my SaveChanges code:

public override int SaveChanges()
{
    var changeSet = ChangeTracker.Entries<IAuditable>();

    if (changeSet != null)
    {
        foreach (var entry in changeSet.Where(c => c.State != EntityState.Unchanged))
        {
            entry.Entity.ModifiedDate = DateProvider.GetCurrentDate();
        }
    }
    return base.SaveChanges();
}

Answer 1

You can use the HttpContext.Current.User.Identity.Name to get the name of the current user.

public override int SaveChanges()
{
    var changeSet = ChangeTracker.Entries<IAuditable>();

    if (changeSet != null)
    {
        foreach (var entry in changeSet.Where(c => c.State != EntityState.Unchanged))
        {
            entry.Entity.ModifiedDate = DateProvider.GetCurrentDate();
            entry.Entity.ModifiedBy = HttpContext.Current.User.Identity.Name;
        }
    }
    return base.SaveChanges();
}

Better way to do this would be to use constructor injection to pass the current user to the context

public class MyContext : DbContext
{
    public MyContext(string userName)
    {
        UserName = userName;
    }

    public string UserName
    {
        get; private set;
    }

    public override int SaveChanges()
    {
       var changeSet = ChangeTracker.Entries<IAuditable>();

       if (changeSet != null)
       {
          foreach (var entry in changeSet.Where(c => c.State != EntityState.Unchanged))
          {
              entry.Entity.ModifiedDate = DateProvider.GetCurrentDate();
              entry.Entity.ModifiedBy = UserName;
          }
       }
       return base.SaveChanges();
   }
}