Unable to create an object of type 'Context'

Question

I'm currently working on a Azure function project In .NET5.

I have the following project structure:

• Function.Application
• Function.Domain
• Function.Infrastructure

When I try to generate a migration, I get the following error:

Unable to create an object of type 'Context'. For the different patterns supported at design time, see https://go.microsoft.com/fwlink/?linkid=851728

Here Is some code:

Function.Application.Program.cs:

public static void Main()
{
    var host = new HostBuilder()
        .ConfigureFunctionsWorkerDefaults()
        .ConfigureServices(services =>
        {
            var localConnectionString = @"Server=(localdb)\mssqllocaldb;Database=information-services-testdb;Integrated Security=True;";
            services.AddDomain(localConnectionString);
        })
        .Build();

    host.Run();
}

Function.Domain.Injections:

public static class Injections
{
    public static IServiceCollection AddDomain(this IServiceCollection services, string connectionString)
    {
        services.AddPersistence(connectionString);

        return services;
    }
}

Function.Infrastructure.Injections:

public static class Injections
{
    public static IServiceCollection AddPersistence(this IServiceCollection services, string connectionString)
    {
        services.AddDbContext<IContext, Context>(
            options => options.UseSqlServer(connectionString),
            ServiceLifetime.Transient,
            ServiceLifetime.Transient);

        return services;
    }
}

This approach works well when I develop regular ASP.NET Core applications. I just choose which project the Context are In, and then just type Add-migration dbInit, and It works.

Why does this not work when working with Azure Functions?

Answer 1

Run below command to find the real problem.

Add-Migration Init -Verbose

There are a lot of ways to help you solve the issues.

1. Can add a class that implements IDesignTimeDbContextFactory inside of your Web project.

2. Find real problem and change your code.

For more details , pls check below post.

Unable to create migrations after upgrading to ASP.NET Core 2.0