C# 实体框架核心：无法解析服务

Question

I'm trying to use Entity Framework Core for C# for the first time. My project does compile, but my add-migration does not run.

I get the error:

Unable to resolve service for type 'Microsoft.EntityFrameworkCore.Storage.TypeMappingSourceDependencies' while attempting to activate 'MySql.EntityFrameworkCore.Storage.Internal.MySQLTypeMappingSource'.

My project file:

<Project Sdk="Microsoft.NET.Sdk.Web">
  <PropertyGroup>
    <TargetFramework>net6.0</TargetFramework>
    <Nullable>enable</Nullable>
    <ImplicitUsings>enable</ImplicitUsings>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="BCrypt.Net-Next" Version="4.0.2" />
    <PackageReference Include="EntityFramework" Version="6.4.4" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="6.0.1">
      <PrivateAssets>all</PrivateAssets>
      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
    </PackageReference>
    <PackageReference Include="MySql.EntityFrameworkCore" Version="6.0.0" />
    <PackageReference Include="Swashbuckle.AspNetCore" Version="6.2.3" />
  </ItemGroup>
</Project>

My DbContext:

internal class DbModelContext : DbContext
{
    public DbSet<DbUser> Users { get; set; }    
    public DbModelContext(DbContextOptions<DbModelContext> options)
        : base(options) { }
}

My user table:

internal class DbUser
{
    [Key]
    public string? Email { get; set; }
    public string? PasswordHash { get; set; }
    public Guid UserId { get; set; }
}

Here is my Program.cs (im using net6 so i dont have a startup.cs)

//Init DbConnectorClass
DatabaseConnector dbConnector = new();

WebApplicationBuilder builder = WebApplication.CreateBuilder(args);

builder.Services.AddControllers();
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

//TODO: move to appsettings.json
var connString = "server=192.168.178.XXX;user=XXX;database=XXX;password=XXX;port=3306";

builder.Services.AddDbContext<DbModelContext>(options => options.UseMySQL(connString));
builder.Services.AddScoped<IAuthenticationHandler>(ah => new AuthenticationHandler(dbConnector));

WebApplication app = builder.Build();

app.UseSwagger();
app.UseSwaggerUI();

app.UseHttpsRedirection();
app.UseAuthorization();
app.MapControllers();
app.Run();

Answer 1

如果您正确设置数据库，请尝试使用此命令“dotnet ef migrations add Initial”进行更新尝试“dotnet ef database update”

"

Answer 2

im using net6 so i dont have a startup.cs

<\/blockquote>

Answer 3

<PackageReference Include="EntityFramework" Version="6.4.4" />

Answer 4

public class MysqlEntityFrameworkDesignTimeServices : IDesignTimeServices
{
    public void ConfigureDesignTimeServices(IServiceCollection serviceCollection)
    {
        serviceCollection.AddEntityFrameworkMySQL();
        new EntityFrameworkRelationalDesignServicesBuilder(serviceCollection)
            .TryAddCoreServices();
    }
}

You can add one another class in startup.cs file, in order to get this fixed.