Help my dog is constipated and i don;t know what to do?

hello i have a papillon breed dog and she is constipated. when she poops it will take her a bit of time as he moves in different stops to poop. i have tried her with the wet food and she poops to much and it is like she gets sick from that stuff. my question is dose anyone know a dry dog food that can help my dog as i don;t want her on wet food at all thanks