Question

Given:

using (DataContext ctx = new DataContext(props.ConnectionString))
{
    IQueryable<Email> emails = null;
    try
    {
       emails = ctx.Emails.Where(e => !(e.IsLocked || e.IsSent));
       foreach (var e in emails)
       {
           e.IsLocked = true;
       }
       ctx.SubmitChanges();
    }
}

// do something with emails here

Why is emails empty after SubmitChanges()? Is there any way to avoid emptying the Table after IsLocked is set to true?

Answer 1

The table ctx.Emails is probably not empty. The collection emails is evaluated every time you call it.

You could do this if you want to keep the emails return on the initial call:

emails = ctx.Emails.Where(e => !(e.IsLocked || e.IsSent)).ToList().AsQueryable();