Compare two Combobox strings

I'm trying to compare two strings, the selected field from a Combobox and just a string. I tried several things but for some reason it always hits the else statement. Why? I already tried to use Platform::string instead of std::string but no result. The selected input is "Nvidia".

void N_Body::MainPage::comboBox_SelectionChanged(Platform::Object^ sender, Windows::UI::Xaml::Controls::SelectionChangedEventArgs^ e)
{
    comboBox_2->Items->Clear();

    Object^ selectedItem = comboBox_2->SelectedItem;

    Platform::String^ Nvidia("Nvidia");

    //if (selectedItem->ToString() == "Nvidia") doesn't seem to work either..
    if (selectedItem->ToString() == Nvidia) {
        comboBox_2->Items->InsertAt(0, "CUDA");
        comboBox_2->Items->InsertAt(1, "C++ AMP");
    }
    else {
        comboBox_2->Items->InsertAt(0, "C++ AMP");
    }

}