Caution

The ApplicationContext is obsolete. Use dependency injection instead!

Obsolete: ApplicationContext: Passing parameters to Migrations

ApplicationContext is an object passed in by the Migration Runner that is available to migrations to be used as a switch.

To set the ApplicationContext when running migrate.exe

Run migrate.exe ... --context MyArgument. This will set the application context to the string MyArgument.

To set the ApplicationContext when running migration in code

Set migratorConsole.ApplicationContext to an arbitrary C# object, such as a string: migratorConsole.ApplicationContext = "MyArgument"; or when creating the RunnerContext:

var migrationContext = new FluentMigrator.Runner.Initialization.RunnerContext(announcer)
{
    ApplicationContext = "MyArgument"
};

To use the ApplicationContext

Inside your migration, you can access the context via this.ApplicationContext. So for instance:

if ((string)this.ApplicationContext == "MyArgument")
    this.Delete.Column("BadColumn").FromTable("MyTable");

Alternative: DependencyInjection

Just register your service and use it in your migration:

interface IMyService {
    string MyStringData { get; }
}

class MyService : IMyService {
    public string MyStringData { get; set; }
}

static void Main() {
    var serviceProvider = new ServiceCollection()
        .AddFluentMigratorCore()
        // TODO: Configure database and connection
        .AddSingleton<IMyService>(new MyService() { MyStringData = "MyArgument" })
        .BuildServiceProvider();

    var runner = serviceProvider.GetRequiredService<IMigrationRunner>();
    // TODO: Use the runner
}

[Migration(1234)]
public class MyMigration : ForwardOnlyMigration {
    private readonly IMyService _service;

    public MyMigration(IMyService service) {
        _service = service;
    }

    public void Up() {
        if (_service.MyStringData == "MyArgument")
            Delete.Column("BadColumn").FromTable("MyTable");
    }
}