How do you add to an ICollection list and save it to a database without gettingan object disposed exception? (Entity Framework)

Question

Lets say we have a class like this:

public class SampleClass
{

    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int ID { get; set; }

    public virtual ICollection<ScoreData> ScoreData{ get; set; }
}

And another class like this:

public class ScoreData
{
    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int Id {get; set;}
    public int subSectionScore {get; set;}

    public int SampleClassID { get; set; }
    public virtual SampleClass SampleClass { get; set; }
}

Why does this throw an object disposed exception and how can it be fixed?

internal static void CalculatesubSectionScores(ref List<SampleClass> sampleClassData)
{

    foreach (var item in sampleClassData)
    {
        item.ScoreData= new List<ScoreData>();

        /* code in second foreach accesses another objects item to 
           use for each sub sections calculations*/

        foreach ()
        {
           var scoringData = new ScoreData();
           var score = 0.0;
           scoringData.subSectionScore = score;

           item.ScoreData.Add(scoringData);
        }
    }

I've removed most of the logic from this class just to focus on the problem at hand.

Answer 1

Declare ScoreData before adding to it

internal static void CalculatesubSectionScores(ref List<SampleClass> sampleClassData)
{

    foreach (var item in sampleClassData)
    {
        item.ScoreData= new List<ScoreData>();

        /* code in second foreach accesses another objects item to 
           use for each sub sections calculations*/

        item.ScoreData = new List<ScoreData>();  // Add This Line

        foreach ()
        {
           var scoringData = new ScoreData();
           var score = 0.0;
           scoringData.subSectionScore = score;

           item.ScoreData.Add(scoringData);
        }
    }
}