Question

class MyClass<T> where T: new()
{
    public Test()
    {
        var t = new T();
        var t = new T("blah"); // <- How to do this?
    }
}

I know that’s not possible as written, and as far as I understand it’s just simply not allowed (although I would love nothing more than to be wrong about that). The first solution that comes to mind is to use an object initializer, but let’s suppose that’s a last resort because it would conflict with other oop goals in this case.

My next inclination would be to use reflection, but before I do that I’d like to know if I am overlooking any easier way to do this or perhaps a different design pattern that would work better?

Answer 1

You can’t do it directly. You’ll need to use Activator.CreateInstance, but doing so has all the drawbacks of reflection, meaning that you miss out on compile-time checking etc.

public Test()
{
    var t = (T)Activator.CreateInstance(typeof(T), (object)"blah");
}