Why are my LINQ INSERTS not persisting in SQL Server CE 3.5?

问题

I am using LINQ to SQL with Sql Server Compact Edition 3.5 and VS2008.

I have a very simple table (Tokens) with a uniqueidentifier primary key (TokenID) and two other nullable fields (UsedBy and UsedOn). I am trying to use LINQ to insert new rows into the table but for some reason they are not persisting.

Here is my code:

        var connectionstring = "Data Source=|DataDirectory|\\MyData.sdf";
        MyData db = new MyData(connectionstring) { Log = Console.Out };

        Tokens token = new Tokens { TokenID = Guid.NewGuid() };
        db.Tokens.InsertOnSubmit(token);
        //db.GetChangeSet();
        db.SubmitChanges();

        var tokens = from t in db.Tokens
                     select t;
        foreach (var t in tokens)
        {
            Debug.Print(t.TokenID.ToString());
        }

If I uncomment db.GetChangeSet(); I can see the pending insert and when I iterate and print them to the debug widow the # of tokens grows each time. But if I query the table in VS (via Show Table Data) it is empty? Viewing the data like this also "resets" the tokens returned by LINQ their original state.

I am pretty sure I am making some simple mistake, but I can't see it. Any ideas?

回答1:

Check that your DB file is not copied to the output directory at each build (in the property page of the project item)

回答2:

Of course 5 minutes after posting my question I have a huge DUH! moment. Turns out I was refreshing the database in my project to see if the inserts were persisting when I should have been checking \bin\Debug\MyData.sdf instead.

Trust the code Sean, trust the code. Oh, and remember you're an idiot sometimes.

来源：https://stackoverflow.com/questions/1343816/why-are-my-linq-inserts-not-persisting-in-sql-server-ce-3-5