Using a custom ListView in the Forms designer

I have a ListView in my Form in which I would like to override the IsInputKey method.   I create the override like this:

public ref class myListView : ListView
{
    protected: virtual bool IsInputKey(Keys keyData) override 
    {
        if (keyData == Keys::Left || keyData == Keys::Right)
        {
            return true;
        }
        else
        {
            return ListView::IsInputKey(keyData);
        }
    }

};

But then how do I use myListView in the designer instead of ListView? 

I tried changing the form designer code from:

private: System::Windows::Forms::ListView^  listView1;

this->listView1= (gcnew System::Windows::Forms::ListView());

to:

private: myListView^  listView1;

this->listView1= (gcnew customListView());

This doesn't seem to work though since the gcnew line is within the  "#pragma region Windows Form Designer generated code" block which has comments saying not to modify it's contents.

Is there a proper way to do this?

Thanks