Question

First tread on stack overflow, i will try to do my best..

Below, my model from ADO.NET (mysql database)

http://img585.imageshack.us/img585/4533/screenshot20120519at143.png

// CHECK USER+PASS
rmEntities2 myDb = new rmEntities2();
var query = from c in myDb.users
            where c.use_login == run.name
            where c.use_password == run.pass
            select c.use_id;

if (query.Count() == 0)
{
    return "ERROR USER/PASSWORD";
}
else
{
    // Linq insert DB
    running newRun = new running();
    newRun.run_start_time = new System.DateTime(1970, 1, 1, 0, 0, 0, 0)
        .AddSeconds(Double.Parse(run.start));
    newRun.run_end_time = new System.DateTime(1970, 1, 1, 0, 0, 0, 0)
        .AddSeconds(Double.Parse(run.stop));
    newRun.run_distance = (float)run.distance;
    newRun.run_nbfootsteps = run.nbfootsteps;
    newRun.run_vo2max = run.vo2Max;

    foreach (int u in query)
    {
        newRun.user.use_id = u;
    }

    myDb.AddTorunnings(newRun);
    myDb.SaveChanges();
    return "RUNNING ADDED";
}

The problem is from this line :

newRun.user.use_id = u;

I would like set up the run_use_id from user in my running table.

What is the best way?

Answer 1

I expect that when you try to set the use_id value in the line

newRun.user.use_id = u;

you’re getting a NullReferenceException. This is because newRun.user is null – the new run is not associated with a user.

I’d suggest that instead of working with the use_id, instead work with the user.

var query = from c in myDb.users
            where c.use_login == run.name
            where c.use_password == run.pass
            select c;
var user = query.SingleOrDefault();

and then either of these:

newRun.user = user; 
// or 
user.runnings.Add(newRun);

They both do the same thing, but use whichever makes more sense to you.