Question

我正在尝试从另一个.NET Core项目添加ApiAuthorizationDbContext的迁移，但是由于我不知道如何获取第二个参数IOptions<OperationalStoreOptions>，所以无法在设计时实例化它。

这是我的DbContext构造函数（继承了我的自定义ApiAuthorizationDbContext，它接受TUser，TRole和TKey）

public class ApplicationDbContext : ApiAuthorizationDbContext<ApplicationUser, ApplicationRole, Guid>
{
    public ApplicationDbContext (DbContextOptions options, IOptions<OperationalStoreOptions> operationalStoreOptions)
        : base(options, operationalStoreOptions)
    {
    }

这是我的DesignTimeDbContextFactory

public class DesignTimeDbContextFactory : IDesignTimeDbContextFactory<KontestDbContext>
{
    public ApplicationDbContext CreateDbContext(string[] args)
    {
        IConfiguration configuration = new ConfigurationBuilder()
            .SetBasePath(Directory.GetCurrentDirectory())
            .AddJsonFile("appsettings.json").Build();

        var builder = new DbContextOptionsBuilder<ApplicationDbContext>();
        var connectionString = configuration.GetConnectionString("DefaultConnection");
        builder.UseSqlServer(connectionString);

        return new ApplicationDbContext(builder.Options, ????); <--- how to resolve the IOptions<OperationStoreOptions> here ??
    }
}

我从this issue in GitHub找到了答案，但仍然找不到解决该参数的方法。

我还尝试将IOptions <>注入构造函数，但是在添加迁移时，它抛出一个异常，即找不到DesignTimeDbContextFactory的无参数构造函数

有人可以给我一个提示吗，我在这里对.NET Core / EF Core还是很陌生，如果有人可以提供帮助，我将非常感谢！

（我正在使用.NET Core 3.0和Entity Framework Core）

Answer 1

继承 IOptions 创建 OperationalStoreOptionsMigrations ，并传递 OperationalStoreOptionsMigrations 对象。看看我的答案。

创建 OperationalStoreOptionsMigrations 方法。

 public class OperationalStoreOptionsMigrations : 
   IOptions<OperationalStoreOptions>
 {
       public OperationalStoreOptions Value => new OperationalStoreOptions()
       {
             DeviceFlowCodes = new TableConfiguration("DeviceCodes"),
             EnableTokenCleanup = false,
             PersistedGrants = new TableConfiguration("PersistedGrants"),
             TokenCleanupBatchSize = 100,
             TokenCleanupInterval = 3600,
       };
 }

更改 DesignTimeDbContextFactory

 public class DesignTimeDbContextFactory : 
   IDesignTimeDbContextFactory<KontestDbContext>
 {
     public ApplicationDbContext CreateDbContext(string[] args)
     {
             IConfiguration configuration = new ConfigurationBuilder()
             .SetBasePath(Directory.GetCurrentDirectory())
             .AddJsonFile("appsettings.json").Build();

             var builder = new DbContextOptionsBuilder<ApplicationDbContext>();
             var connectionString = 
                 configuration.GetConnectionString("DefaultConnection");
                 builder.UseSqlServer(connectionString);

             return new ApplicationDbContext(builder.Options, new OperationalStoreOptionsMigrations()); 
        }
   }

Answer 2

在构造函数中将IOptions<OprerationalStoreOption>作为参数传递，然后可以在需要的地方使用它。然后在IOptions容器中注册DI服务。像这样

public ApplicationDbContext CreateDbContext(string[] args, Options<OperationStoreOptions> optionsBuilder)
    {
        IConfiguration configuration = new ConfigurationBuilder()


        return new ApplicationDbContext(builder.Options, optionsBuilder);
    }

从另一个项目为ApiAuthorizationDbContext添加迁移-EF Core

2 个答案: