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();

CodePudding user response：

if you setup your database properly then try this command "dotnet ef migrations add Initial" for update try "dotnet ef database update"

CodePudding user response：

im using net6 so i dont have a startup.cs

This is the root cause of the problem. From Design-time DbContext Creation documentation topic, even though not stated explicitly, looks like that "minimal API" style code is not supported, since they still need a special method

public static IHostBuilder CreateHostBuilder(string[] args)

in the Program class. Hence most likely you need to move most of your code (between CreateBuilder(args) and .Build()) into a method with the above signature. Or use other methods of creating db context at design time, for instance From a design-time factory and somehow get the settings needed to create the db context. I guess refactoring the startup code would be easier.

There is a (closed?!) issue on EF Core GitHub issue tracker - #3557: How to access to WebHostBuilder in Design-time DbContext Creation with top-level statements?. I posted a comment there asking for updating the documentation and providing an example for "minimal API" projects, and included a link to your question. You can watch EF Core team responses there and eventually see what is their vision on the subject.

CodePudding user response：

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

This is not Entity Framework core, but the old EF 6. You need to install/replace it with

<PackageReference Include="Microsoft.EntityFrameworkCore" Version="6.0.1" />

Or the version of your liking.

Also, the MySql provider you are using is not so great. You might want to switch to Pomelo