I'm not sure that there is a DVI to iPad 2 cable. There is an HDMI cable adaptor (named 30 pin Digital AV which is rather confusing) and there is a VGA cable. You will probably need an HDMI - DVI adaptor. But you will have to make sure that you have the right hdmi end. When it is connected you should be able to mirror the ipad display on the TV but it may not fill the entire screen.
OnePlus 5 review