Question

I am new to developing in .NET and C#, but have been a long-time developer, working with C, C++, Java, PHP, etc.

I have an MVC3 extension class for my data models that refers to the database. It is set as “private static” in the class, but I think that it is not keeping up with database changes. In other words, when I change data in the controllers, those changes aren’t “noticed” in the db because it is static. Currently, I am creating and disposing of the variable for each use, to compensate.

My questions are:

1. Am I correct that a static db variable could behave that way?
2. Is it necessary to dispose of the dynamic variable in the static class, or will garbage collection still take care of it automatically?

Here is a relevant snippet of the class:

namespace PBA.Models {
    using System;
    using System.Text.RegularExpressions;
    using PBA.Models;
    using PBA.Controllers;

    public static class Extensions {
        private static PbaDbEntities db = null;

        public static PbaDbEntities GetDb() {
            // TODO: find out about static memory/disposal, etc.
            //
            if (db != null) {
                db.Dispose();
            }
            db = new PbaDbEntities();
            return db;
        }

        public static string GetCheckpointState(this Activity activity, long memberProjectId) {
            GetDb();  // TODO: Do I need to do this each time, or will a one-time setting work?

            string state = CheckpointController.CHECKPOINT_STATUS_NOT_STARTED;
            try {
                var sub = db.ActivitySubmissions.
                    Where(s => s.activityId == activity.activityId).
                    Where(s => s.memberProjectId == memberProjectId).
                    OrderByDescending(s => s.submitted).
                    First();
                if (sub != null) {
                    state = sub.checkpointStatusId;
                }
            }
            catch (Exception e) {
// omitted for brevity
                }
                return state;
            }
        }
    }

Answer 1

Your code will fail horribly in production.
DataContexts are not thread-safe; you must not share a context between requests.

Never put mutable objects in static fields in multi-threaded applications.