Question

我有一个网站，可以收集来自用户的电子邮件的输入（向所有人发送电子邮件，他们点击一个调用控制器操作的链接）。我想使用webjob发送电子邮件，但我需要遍历数据库中的所有用户以获取电子邮件地址。

我建立了网站，一切都很好。我在这里继承了IdentityDbContext的DbContext：

public class MooodDbContext : IdentityDbContext<ApplicationUser>
    {
        public MooodDbContext(DbContextOptions options) : base(options)
        {

        }

        public DbSet<Response> Response { get; set; }

        public DbSet<Cow> Cow { get; set; }

        public DbSet<Herd> Herd { get; set; }
    }

我启动webapp

时会运行ConfigureServices

public void ConfigureServices(IServiceCollection services)
        {
            // Add framework services.
            services.AddDbContext<MooodDbContext>(options =>
                options.UseSqlServer(Configuration.GetConnectionString("MooodConnection")));

            services.AddIdentity<ApplicationUser, IdentityRole>()
                .AddEntityFrameworkStores<MooodDbContext>()
                .AddDefaultTokenProviders();

            services.AddMvc(options => options.Filters.Add(typeof(UnauthorizedExceptionFilterAttribute)));

            services.AddScoped<IDbInitializer, DbInitializer>();

            // Add application services.
            services.AddTransient<IEmailSender, AuthMessageSender>();
            services.AddTransient<ISmsSender, AuthMessageSender>();

        }

但显然不是我运行webjob时。因此，当我尝试访问上下文中的任何内容时，我得到此异常（在设置context = new context（）之后）：

System.InvalidOperationException occurred
  HResult=0x80131509
  Message=No database provider has been configured for this DbContext. A provider can be configured by overriding the DbContext.OnConfiguring method or by using AddDbContext on the application service provider. If AddDbContext is used, then also ensure that your DbContext type accepts a DbContextOptions<TContext> object in its constructor and passes it to the base constructor for DbContext.
  Source=Microsoft.EntityFrameworkCore

在我看来，这是因为我没有对DbContext进行任何配置，但我不确定。有没有更好的方法来实现这一目标？或者我错过了一些小事？

编辑：这是我的webjob的program.cs（减去电子邮件功能，这是杂乱的）：

private static MooodDbContext _context;

        // Please set the following connection strings in app.config for this WebJob to run:
        // AzureWebJobsDashboard and AzureWebJobsStorage

        private static void Main()
        {
            _context = new MooodDbContext(new DbContextOptions<MooodDbContext>());

            var host = new JobHost();

            EmailAllHerds();

            host.RunAndBlock();

            EmailAllHerds();
        }

Answer 1

我在这里做了几个假设

web job是一个基于.net核心的控制台应用程序

因此，您将拥有一个带有main方法的Program.cs文件。所以在你的

<强> Program.cs的

class Program {
   // declare a field to store config values
   private readonly IConfigurationRoot _configuration;
   // Declare a constructor 
   public Program()
   {
       var builder = new ConfigurationBuilder()
            .SetBasePath(environment.BasePath)
            .AddJsonFile($"appsettings.json", true, true)
            .AddJsonFile($"appsettings.{environment.EnvironmentName}.json", true, true)
            .AddEnvironmentVariables();

        _configuration = builder.Build();
   }
 }
  public static void Main(string[] args)
  {
     var program = new Program();
     var serviceCollection = new ServiceCollection();
     program.ConfigureServices(serviceCollection);           

  }

    private void ConfigureServices(IServiceCollection services)
    {
       // now here you can resolve your DbContext similar to web
      services.AddDbContext<MooodDbContext>(options =>options.UseSqlServer(_configuration.GetConnectionString("MooodConnection")));
    }
}

从webjob

1 个答案: