Abstract Factory or Factory Method for types with different constructor arguments

Question

I have a factory method as given below. Is there a better way to design this so I do not have to use switch statement and achieve open closed principle

public IPolicy CreatePolicy(Context context)
{
    IPolicy policy = default(IPolicy);
    ISettings settings = _settings.Get(context);
    Policy policyType = (Policy) Enum.Parse(typeof(Policy), settings.Policy);
    switch (policyType)
    {
        case Policy.Policy1:
            policy = new Policy1(_policy1Service, _logHandler);
            break;
        case Policy.Policy2:
            policy = new Policy2(_policy2Service, _logHandler);
            break;
        case Policy.Policy3:
            policy = new Policy3(_policy1Service, _policy2Service, _logHandler);
            break;
    }
    return policy;
}

Answer 1

Supposed the enum literals are exactly the same as your class names, you could dynamically create the instances based on the enum literal like

public static IPolicy CreatePolicy(Policy policy)
{
    //Change this if the namespace of your classes differs
    string ns = typeof(Policy).Namespace;

    string typeName = ns + "." + policy.ToString();

    return (IPolicy)Activator.CreateInstance(Type.GetType(typeName));
}

Passing constructor parameters is also possible by simply adding them like

return (IPolicy)Activator.CreateInstance(Type.GetType(typeName),
    _policy1Service, _logHandler);

Since this is very unusual, think about adding an Initialize(...) method to IPolicy to pass these parameters to allow an empty constuctor.