Registering open generic singleton using Simple Injector

Question

I have the below code, and would like to register a singleton for each different variant of the generic. Is this possible? Currently, the assertion fails, as the are not the same object type.

public interface IGenericClass<T>
{
    string GetToString();
}

public class GenericClass<T> : IGenericClass<T>
{
    public string GetToString()
    {
        return typeof (T).FullName;
    }
}

[Test]
public void test()
{
    var container = new Container();

    container.RegisterOpenGeneric(
        typeof(IGenericClass<>), 
        typeof(GenericClass<>));

    var instance1 = container.GetInstance<IGenericClass<double>>();
    var instance2 = container.GetInstance<IGenericClass<double>>();

    //this should assert true
    Assert.IsTrue(object.ReferenceEquals(instance1, instance2));
}

Answer 1

Just use RegisterSingleOpenGeneric:

_container.RegisterSingleOpenGeneric(
    typeof(IGenericClass<>), 
    typeof(GenericClass<>));