Lisa Posts - Answer Overflow

Lisa

•Created by Lisa on 5/8/2025 in #help

✅ Nested Record Inheritance

I'm trying a bit of inheritance shenanigans, the API I'm working with wraps everything in a data object, which usually has two fields that always appear:

public abstract record CharacterActionResult([property: JsonPropertyName("data")] CharacterActionResultData Data);

public abstract record CharacterActionResultData(
    [property: JsonPropertyName("cooldown")] Cooldown Cooldown,
    [property: JsonPropertyName("character")] Character Character
);

public abstract record CharacterActionResult([property: JsonPropertyName("data")] CharacterActionResultData Data);

public abstract record CharacterActionResultData(
    [property: JsonPropertyName("cooldown")] Cooldown Cooldown,
    [property: JsonPropertyName("character")] Character Character
);

This way I can keep a base record for when I need to access cooldown/character in a generic method, but I can still the define the fields that are different:

public record FightResult(FightResultData Data) : CharacterActionResult(Data);

public record FightResultData(
    [property: JsonPropertyName("fight")] Fight Fight,
    Cooldown Cooldown,
    Character Character
) : CharacterActionResultData(Cooldown, Character);

public record FightResult(FightResultData Data) : CharacterActionResult(Data);

public record FightResultData(
    [property: JsonPropertyName("fight")] Fight Fight,
    Cooldown Cooldown,
    Character Character
) : CharacterActionResultData(Cooldown, Character);

However, I get an error:

0>FightResult.cs(6,43): Error CS8866 : Record member 'Artifacts.Model.Characters.CharacterActionResult.Data' must be a readable instance property or field of type 'Artifacts.Model.Characters.FightResultData' to match positional parameter 'Data'.

Am I looking over something?

19 replies

CC#

•Created by Lisa on 6/28/2024 in #help

✅ Unable to create migration - 'Unable to resolve service for type 'DbContextOptions'

This is my first time creating migrations (never had a need until now), so please bear with me. I'm trying to use dotnet ef migrations add AMigrationName to add a migration to my project, However, I get this error:

Unable to create a 'DbContext' of type ''. The exception 'Unable to resolve service for type 'Microsoft.EntityFrameworkCore.DbContextOpt
ions`1[Treehouse_Guardian.Database.DatabaseContext]' while attempting to activate 'Treehouse_Guardian.Database.DatabaseContext'.' was th
rown while attempting to create an instance. For the different patterns supported at design time, see https://go.microsoft.com/fwlink/?l
inkid=851728

Unable to create a 'DbContext' of type ''. The exception 'Unable to resolve service for type 'Microsoft.EntityFrameworkCore.DbContextOpt
ions`1[Treehouse_Guardian.Database.DatabaseContext]' while attempting to activate 'Treehouse_Guardian.Database.DatabaseContext'.' was th
rown while attempting to create an instance. For the different patterns supported at design time, see https://go.microsoft.com/fwlink/?l
inkid=851728

My startup looks like this:

private Program()
{
    _configuration = new ConfigurationBuilder()
        .AddJsonFile("appsettings.json", optional: false)
        .Build();

    _serviceProvider = new ServiceCollection()
        .AddSingleton(_configuration)
        .AddSingleton(ConfigureDiscordSocketConfig)
        .AddSingleton(ConfigureDiscordSocketClient)
        .AddSingleton<InteractionService>()
        .AddSingleton<InteractionHandler>()
        .AddSingleton<WritingService.WritingService>()
        .AddSingleton<TreehouseMemberService>()
        .AddSingleton<BenzHandler>()
        .AddSingleton<GniHandler>()
        .AddSingleton<HttpClient>()
        .AddDbContext<DatabaseContext>(ConfigureDbContext)
        .BuildServiceProvider();
    
    Logger.ConfigureLogging();
}

private Program()
{
    _configuration = new ConfigurationBuilder()
        .AddJsonFile("appsettings.json", optional: false)
        .Build();

    _serviceProvider = new ServiceCollection()
        .AddSingleton(_configuration)
        .AddSingleton(ConfigureDiscordSocketConfig)
        .AddSingleton(ConfigureDiscordSocketClient)
        .AddSingleton<InteractionService>()
        .AddSingleton<InteractionHandler>()
        .AddSingleton<WritingService.WritingService>()
        .AddSingleton<TreehouseMemberService>()
        .AddSingleton<BenzHandler>()
        .AddSingleton<GniHandler>()
        .AddSingleton<HttpClient>()
        .AddDbContext<DatabaseContext>(ConfigureDbContext)
        .BuildServiceProvider();
    
    Logger.ConfigureLogging();
}

And ConfigureDbContext is just:

private void ConfigureDbContext(DbContextOptionsBuilder optionsBuilder)
{
    optionsBuilder.UseNpgsql(_configuration["Postgres:ConnectionString"]);
}

private void ConfigureDbContext(DbContextOptionsBuilder optionsBuilder)
{
    optionsBuilder.UseNpgsql(_configuration["Postgres:ConnectionString"]);
}

My databasecontext looks like this:

using Microsoft.EntityFrameworkCore;
using Treehouse_Guardian.Model;

namespace Treehouse_Guardian.Database;

public class DatabaseContext(DbContextOptions<DatabaseContext> options) : DbContext(options)
{
    public DbSet<TreehouseMember> TreehouseMember
    {
        get;
        set;
    }
}

using Microsoft.EntityFrameworkCore;
using Treehouse_Guardian.Model;

namespace Treehouse_Guardian.Database;

public class DatabaseContext(DbContextOptions<DatabaseContext> options) : DbContext(options)
{
    public DbSet<TreehouseMember> TreehouseMember
    {
        get;
        set;
    }
}

What am I missing? How can I make sure the migration creator can access my dbcontextoptions at design time?

2 replies

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