Can not update object in control action with ASP.NET MVC?

Question

I have a view with a form, when user submit the form, the matched action method is like:

public ActionResult Test(ViewModel vm, Member member)
{
//...
 if (ModelState.IsValid)
  {
     try{
        //...
        member.OID = 1;   //error here
        //...
     }Catch(Exception ex)
     {
      //... 
     }
  }            
}

It works fine before, but now I get error as below when assigning the value to a object property: Operation is not valid due to the current state of the object

why? how to resolve it?

Answer 1

It is not very clear as your code sample, if my guess is right. Member object is LINQ's class where you have OID as a FK to other object in your schema.

The error show that you cannot assign OID directly. say your O is Occupation Id. then you have to

member.Occupation = (from c in dc.Occupation where c.ID = 1 select c);

Hope this helps.