EF Core-System.InvalidOperationException:ExecuteReader需要一个打开

本文关键字：一个 InvalidOperationException Core-System ExecuteReader EF | 更新日期: 2023-09-27 17:59:44

我正在运行一个带有实体框架核心的ASP.NET Core 1.0 web应用程序。当应用程序运行了一段时间（24-48小时）时，应用程序在向任何端点或静态资源发出的每个请求时都会崩溃，并引发错误System.InvalidOperationException: ExecuteReader requires an open and available Connection. The connection's current state is closed.。我只能通过重新启动应用程序池来从中恢复。

我正在配置这样的实体框架：

启动.cs

public void ConfigureServices(IServiceCollection services)
{
        services.AddDbContext<ApplicationDbContext>(options =>
            options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));   
}

我在owin管道中加载数据，使用的扩展方法如下：

启动.cs

app.LoadTenantData();

AppBuilderExtension.cs:

public static void LoadTenantData(this IApplicationBuilder app)
    {
        app.Use(async (context, next) =>
        {
            var dbContext = app.ApplicationServices.GetService<ApplicationDbContext>();        
            var club = dbContext.Clubs.Single(c => c.Id == GetClubIdFromUrl(context));
            context.Items[PipelineConstants.ClubKey] = club;
            await next();
        });
    }

由于该错误只发生在应用程序运行很长时间时，因此很难重现，但我认为这与EF错误地打开和关闭连接有关。

我该如何调试它？我是否错误地使用EF？

EF Core-System.InvalidOperationException:ExecuteReader需要一个打开

我遇到了同样的问题。

我认为同一个dbcontext实例很可能被多个线程并发使用。

您可能需要：services.AddDbContext<ApplicationDbContext>(options => options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")),ServiceLifetime.Transient); 这是一个问题。https://github.com/aspnet/EntityFramework/issues/6491

我的应用程序非常基础（写得很快，运行一次，然后忘记），所以解决上述问题的方法是简单地在执行多表插入的部分引入lock。

    public void CallGooglePlacesAPIAndSetCallback(string websiteName)
    {
        using (var db = new WebAnalyzerEntities())
        {
            IList<IRecord> addressesToBeSearched = db.Rent.Where<IRecord>(o => o.Url.Contains(websiteName) && o.SpatialAnalysis.Count == 0).ToList().Union(db.Sale.Where<IRecord>(oo => oo.Url.Contains(websiteName) && oo.SpatialAnalysis.Count == 0)).ToList();
            foreach (var locationTobeSearched in addressesToBeSearched)
            {
                try
                {
           //this is where I introduced the lock
                    lock (_lock)
                    {
                        dynamic res = null;
                        using (var client = new HttpClient())
                        {
                            while (res == null || HasProperty(res, "next_page_token"))
                            {
                                var url = $"https://maps.googleapis.com/maps/api/geocode/json?address={locationTobeSearched.Address}&key={googlePlacesApiKey}&bounds=51.222,-11.0133788|55.636,-5.6582363";
                                if (res != null && HasProperty(res, "next_page_token"))
                                    url += "&pagetoken=" + res["next_page_token"];
                                var response = client.GetStringAsync(url).Result;
                                JavaScriptSerializer json = new JavaScriptSerializer();
                                res = json.Deserialize<dynamic>(response);
                                if (res["status"] == "OK")
                                {
                                    Tuple<decimal?, decimal?, string> coordinatesAndPostCode = ReadResponse(res["results"][0]);
                                    if (coordinatesAndPostCode != null && coordinatesAndPostCode.Item1.HasValue && coordinatesAndPostCode.Item2.HasValue)
                                    {
           //this is the line where exception was thrown
                                        locationTobeSearched.SpatialAnalysis.Add(new SpatialAnalysis() { Point = CreatePoint(coordinatesAndPostCode.Item1.Value, coordinatesAndPostCode.Item2.Value) });
                                        locationTobeSearched.PostCode = coordinatesAndPostCode.Item3;
                                    }
                                }
                                else if (res["status"] == "OVER_QUERY_LIMIT")
                                {
                                    return;
                                }
                            }
                        }
                    }
                }
                catch (Exception e)
                {
                }
                db.SaveChanges();
            }
        }
    }
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