Question

I’m haing a few problems updating a row in my database using Linq2Sql.

Inside of my model I have two methods for updating and saving from my controller, which in turn receives an updated model from my view.

My model methods like like:

public void Update(Activity activity)
{
    _db.Activities.InsertOnSubmit(activity);
}


public void Save()
{
    _db.SubmitChanges();
}

and the code in my Controller likes like:

[HttpPost]
public ActionResult Edit(Activity activity)
{
    if (ModelState.IsValid)
    {
        UpdateModel<Activity>(activity);
        _activitiesModel.Update(activity);
        _activitiesModel.Save();
    }
    return View(activity);
}

The problem I’m having is that this code inserts a new entry into the database, even though the model item i’m inserting-on-submit contains a primary key field.

I’ve also tried re-attaching the model object back to the data source but this throws an error because the item already exists.

Any pointers in the right direction will be greatly appreciated.

UPDATE:

I’m using dependancy injection to instantiate my datacontext object as follows:

IMyDataContext _db;

public ActivitiesModel(IMyDataContext db)
{
    _db = db;
}

Answer 1

I fixed this issue by re-obtaining and updating my object in the Update method.

Instead of trying to re-attach or get the data context to realise it was the same object that belonged to it before I basically did as follows:

[HttpPost]
public ActionResult Edit(Activity activity)
{
  Activity myActivity = activitiesModel.getActivityById(activity.id);
  myActivity.name = activity.name;
  myActivity.date = activity.date;
  _dbContext.SubmitChanges();
  return View(activity);
}

This isn’t my exact code and to be more precise, I created another partial class to my datacontext and stored my update code in there.