Will my SQL Connection remain open after my dictionary is populated

Question

In the code sample below, will my data context connection stay open once the ListOfLists method is completed? Do I need to explicitly close it, or will it stay open and be available for other methods.

public static Dictionary<int, string > ListOfLists()
        {
            try
            {
                ListDataDataContext db = new ListDataDataContext(GetConnectionString("Master"));

                return db.ListMatchingHeaders
                    .Select(r => new { r.ListRecNum, r.ListName })
                    .ToDictionary(t => t.ListRecNum, t => t.ListName);
            }
            catch (Exception)
            {
                MessageBox.Show("Could not connect to database, please check connection and try again", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                return null;
            }
        }

Answer 1

It's still open. You will need to explicitly dispose/close of the connection or it's possible that you might have memory or connection pool problems. I recommend that you wrap your context around a using block.

public static Dictionary<int, string> ListOfLists()
{
    try
    {
        using (ListDataDataContext db = new ListDataDataContext(GetConnectionString("Master")))
        {
            return db.ListMatchingHeaders
                .Select(r => new { r.ListRecNum, r.ListName })
                .ToDictionary(t => t.ListRecNum, t => t.ListName);
        }
    }
    catch (Exception)
    {
        MessageBox.Show("Could not connect to database, please check connection and try again", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
        return null;
    }
}