Question

目前我正在使用UnitOfWork存储库模式并更改了我的get调用，这样如果内存中没有存储查询，它将查询并使用MemoryCache将查询结果存储在内存中。在将其存储到内存缓存中时，我已经设置好了sql依赖项。

我当前的问题是，如果查询是在任务/后台线程中运行的，那么sql通知看起来并不是线程安全的，并且我没有向主UI线程返回通知。请问我该怎么做？如果SqlDependency不能在另一个线程中完成，有没有办法告诉主线程设置通知？

Sql Dependy Code来自在线项目，可以在https://code.msdn.microsoft.com/How-to-use-SqlDependency-5c0da0b3

找到

人员存储库代码

private static readonly List<ImmediateNotificationRegister<Person>> NotificationRegisters =
    new List<ImmediateNotificationRegister<Person>>();

public PersonRepository(ApplicationDbContext context)
    : base(context)
{ }

public IEnumerable<Person> GetActive()
{
    return Get(x => x.Active, o => o.OrderBy(x => x.CorrespondenceName));
}

public IEnumerable<Person> Get(
    Expression<Func<Person, bool>> filter = null,
    Func<IQueryable<Person>, IOrderedQueryable<Person>> orderBy = null,
    int? numberOfEntities = null,
    IEnumerable<string> includeProperties = null, bool useCache = false)
{
    IQueryable<Person> query = DbSet;
    List<Person> result;

    if (filter != null)
    {
        query = query.Where(filter);
    }

    if (orderBy != null)
    {
        query = orderBy(query);
    }

    var actualNumberOfEntities = int.MaxValue;

    if (numberOfEntities.HasValue)
    {
        actualNumberOfEntities = Math.Max(1, numberOfEntities.Value);
    }

    if (!useCache)
    {
        if (includeProperties != null)
        {
            query = includeProperties.Aggregate(query,
                (current, includeProperty) => current.Include(includeProperty));
        }

        return query.AsExpandable().Take(actualNumberOfEntities).ToList();
    }

    if (MemoryCache.Default[query.ToString()] == null)
    {

        var notification = new ImmediateNotificationRegister<Person>(Context, query);
        notification.OnChanged += NotificationOnChanged;
        NotificationRegisters.Add(notification);

        if (includeProperties != null)
        {
            query = includeProperties.Aggregate(query,
                (current, includeProperty) => current.Include(includeProperty));
        }
        result = query.AsExpandable().Take(actualNumberOfEntities).ToList();
        MemoryCache.Default[query.ToString()] = result;
        return result;
    }

    return ((IEnumerable<Person>)MemoryCache.Default[query.ToString()]).ToList();
}

线程安全SqlDependency

0 个答案: