LINQ not updating on .SubmitChanges()

问题:

Is there any reason something like this would not work?

This is the logic I have used many times to update a record in a table with LINQ:

 DataClasses1DataContext db = new DataClasses1DataContext();
 User updateUser = db.Users.Single(e => e.user == user);
 updateUser.InUse = !updateUser.InUse;
 db.Log = new System.IO.StreamWriter(@"c:\temp\linq.log") { AutoFlush = true };
 db.SubmitChanges();

(updateUser.InUse is a bit field)

For some reason it isn't working. When I check the linq.log it is completely blank.

Could there be a problem with my .dbml? Other tables seem to work fine but I've compared properties in the .dbml and they all match.

It's as if the db.SubmitChanges(); does not detect any updates being required.

回答1:

The table could not be updated properly because it had no primary key. (Actually it had the column but the constraint was not copied when I did a SELECT INTO my dev table). The DataContext class requires a primary key for updates.

回答2:

Is the InUse property a "normal" one as far as LINQ is concerned? (e.g. it's not autogenerated or anything funky like that?)

Alternatively, I don't suppose it's a Nullable<bool> is it, with a current value of null? If so, your update line isn't actually doing anything - for nullable Booleans, !null = null.