Ducktion

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Dynamic Instantiation ​

Dynamic instantiation allows you to specify the instance returned by Ducktion through a callback, which is useful for performing additional configuration on the instance or returning different instances based on certain conditions.

Register a dynamic callback ​

When registering a service, you can use the setCallback method to register a callback that will be called when the service is requested.

csharp
using TheRealIronDuck.Ducktion.Configurators;
using TheRealIronDuck.Ducktion.Enums;

public class MyMonoConfigurator : MonoDiConfigurator
{
        public void Register(DiContainer container)
        {
            container.Register<MyService>().SetCallback(() => {
                // Here you may execute some logic to determine which instance to return
                return new MyService();
            });
        }
}
using TheRealIronDuck.Ducktion.Configurators;
using TheRealIronDuck.Ducktion.Enums;

public class MyMonoConfigurator : MonoDiConfigurator
{
        public void Register(DiContainer container)
        {
            container.Register<MyService>().SetCallback(() => {
                // Here you may execute some logic to determine which instance to return
                return new MyService();
            });
        }
}

TIP

The callback will be executed upon the first request for the service. Depending on the singleton mode, the returned instance may then be stored and returned on subsequent requests.

Overriding the callback ​

You can override the callback of a service by calling the SetCallback method again. It doesn't matter if there was a callback registered before or not.

csharp
using TheRealIronDuck.Ducktion.Configurators;
using TheRealIronDuck.Ducktion.Enums;

public class MyMonoConfigurator : MonoDiConfigurator
{
        public void Register(DiContainer container)
        {
            // Let's assume MyService was already registered
        
            container.Override<MyService>().SetCallback(() => {
                // Here you may execute some logic to determine which instance to return
                return new MyService();
            });
        }
}
using TheRealIronDuck.Ducktion.Configurators;
using TheRealIronDuck.Ducktion.Enums;

public class MyMonoConfigurator : MonoDiConfigurator
{
        public void Register(DiContainer container)
        {
            // Let's assume MyService was already registered
        
            container.Override<MyService>().SetCallback(() => {
                // Here you may execute some logic to determine which instance to return
                return new MyService();
            });
        }
}

INFO

Whenever the callback is overridden, the cached singleton instance will be cleared. This means that the callback will be executed again on the next request.