实体框架不将更改提交到数据库

Question

This is really odd. I'm trying to a simple thing, I'm trying to find an entity, change a field of that entity, and then commit the changes to the database:

using (AppDbContext context = new AppDbContext()) {
    try {
        var member = context.Members.SingleOrDefault(m = m.MembershipNumberId == membershipNo);
        var centre = context.Centres.SingleOrDefault(c => c.CentreId == oldCentreId);

        if (member != null) {
            if (centre != null) {
                member.Centre_id = Centre.id;
                context.SaveChanges();
            }                    
        }
    } catch (Exception e) {
        HandleError(e);
    }
}

So pretty straight forward stuff. However, for some reason no changes are being committed to the the database, and in fact, the EntityState is remaining Modified .

Here's where things get really weird in my view: I put a breakpoint in AppDbContext.SaveChanges() so I could look at the changetracker in debugging.

When I do this, everything looks good, I see my Centre entity in the Unchanged state, and I see my Member entity in the Modified state. When I open the Member entity that is in the ChangeTracker in the watch window, for some reason this makes the code work when I resume, and the database is updated accordingly.

So long story short: SaveChanges doesn't commit changes to the database. But, if I put a breakpoint in save changes, look at the changetracker in the watch window, and then open up the modifed entity ( Member in my example), then just resume, it does work!

So what could be happening when you look at an entity in the changetracker in the watch window that is causing the code to work? I'm at a loss here and would greatly appreciate any help. Thanks in advance.

Answer 1

I've worked out what it was. The Member POCO had the following field on it:

[Required] public virtual Account

A required lazy loaded field. It was spitting out a validation error because it thought there was no account, when I opened the entity in the watch window, however, it was forcing the Lazy loading to kick in, hence loading the Account. I've taken the [Required] off and now it's working.

Now to work out why I wasn't seeing the validation error at first :/