使用Hangfire,Startup.cs中给出的连接字符串throws无法将文件附加为数据库错误

Question

我在我的ASP .Net MVC Web App中使用了Hangfire,它已成功安装.我想使用相同的LocalDb来存储Hangfire的排队作业,以便像我以前用于存储数据一样出列和处理.但是我遇到下面的错误,当我提供了定义它的connectionString或名称Web.config中Startp.cs.我在添加时没有遇到任何麻烦,在hangfire之前删除了同一localDb中的更新数据.

Cannot attach the file 'c:\users\jerry_dev\documents\visual studio 2013\Projects\Hangfire.Highlighter\Hangfire.Highlighter\App_Data\aspnet-Hangfire.Highlighter-20150113085546.mdf' as database 'aspnet-Hangfire.Highlighter-20150113085546'.

Startup.cs:

public void Configuration(IAppBuilder app)
        {
            ConfigureAuth(app);
            app.UseHangfire(config =>
            {
                string hangfireConnectionString = @"Data Source=(LocalDb)\v11.0;AttachDbFilename=|DataDirectory|\aspnet-Hangfire.Highlighter-20150113085546.mdf;Initial Catalog=aspnet-Hangfire.Highlighter-20150113085546;Integrated Security=True";
                config.UseSqlServerStorage(hangfireConnectionString);
                config.UseServer();
            });
        }

我的项目解决方案名为"Hangfire.Highlighter"

Web.config:

<connectionStrings>
    <add name="DefaultConnection" connectionString="Data Source=(LocalDb)\v11.0;AttachDbFilename=|DataDirectory|\aspnet-Hangfire.Highlighter-20150113085546.mdf;Initial Catalog=aspnet-Hangfire.Highlighter-20150113085546;Integrated Security=True" providerName="System.Data.SqlClient" />
</connectionStrings>

Answer 1

我知道这已经过时了 - 但是已经有9个月了,我也把头发拉了过来 - 并决定在这里写一篇文章.

我的解决方案是创建一个快速而脏的DbContext,将其指向正确的连接字符串,并在构造函数中调用Database.CreateIfNotExists:

public class HangfireContext : DbContext
{
    public HangfireContext() : base("name=HangfireContext")
    {
        Database.SetInitializer<HangfireContext>(null);
        Database.CreateIfNotExists();
    }
}

在HangfireBootstrapper.Start()方法中,我执行以下操作:

public void Start()
{
    lock (_lockObject)
    {
        if (_started) return;
        _started = true;

        HostingEnvironment.RegisterObject(this);

        //This will create the DB if it doesn't exist
        var db = new HangfireContext();

        GlobalConfiguration.Configuration.UseSqlServerStorage("HangfireContext");

       // See the next section on why we set the ServerName
        var options = new BackgroundJobServerOptions()
        {
            ServerName = ConfigurationManager.AppSettings["HangfireServerName"]
        };

        _backgroundJobServer = new BackgroundJobServer(options);

        var jobStarter = DependencyResolver.Current.GetService<JobBootstrapper>();

        //See the Recurring Jobs + SimpleInjector section
        jobStarter.Bootstrap();

    }
}

不确定为什么Hangfire在LocalDb上遇到这么困难 - 也许它只能处理成熟的SQL实例？无论哪种方式,这适用于我,新团队成员,以及站起来的新dev/staging/prod实例.

Answer 2

DB已经创建了吗？您可以尝试使用不同的连接字符串格式吗？类似这样的“Server=.;Database=HangFire.Highlighter;Trusted_Connection=True;”