Is it obligatory in islam to continue to have more children when you can't provide for your existing children?

I heard somewhere that you should never stop having children based on wealth. I.e. if you hardly have any money to provide for your family, you should not let this stop you from having more and more children. Is this Islamic or cultural? I know people who have 10 children, husband and wife, and even grandparents all living, sleeping, and cooking in 1 room. And then they go and have even more children. Is that what we're supposed to do in Islam, is this right? Is it wrong not to have any children, and/or is it wrong to have just 1 or 2 children? Therefore, is it haram not to have lots and lots of children due to lack of wealth?