Only hadith and Quran, that's what I like.
About eating dogs:
عَنِ ابْنِ عَبَّاسٍ، قَالَ نَهَى رَسُولُ اللَّهِ صلى الله عليه وسلم
عَنْ كُلِّ ذِي نَابٍ مِنَ السِّبَاعِ وَعَنْ كُلِّ ذِي مِخْلَبٍ مِنَ
الطَّيْرِ .
Ibn 'Abbas reported that Allah's Messenger peace be upon him
prohibited the eating of all fanged beasts of prey, and all the birds
having talons.
sahih muslim
This is a general rule!
About keep them:
عَنْ أَبِي هُرَيْرَةَ ـ رضى الله عنه ـ قَالَ قَالَ رَسُولُ اللَّهِ
صلى الله عليه وسلم " مَنْ أَمْسَكَ كَلْبًا فَإِنَّهُ يَنْقُصُ كُلَّ
يَوْمٍ مِنْ عَمَلِهِ قِيرَاطٌ، إِلاَّ كَلْبَ حَرْثٍ أَوْ مَاشِيَةٍ
". قَالَ ابْنُ سِيرِينَ وَأَبُو صَالِحٍ عَنْ أَبِي هُرَيْرَةَ عَنِ
النَّبِيِّ صلى الله عليه وسلم " إِلاَّ كَلْبَ غَنَمٍ أَوْ حَرْثٍ
أَوْ صَيْدٍ ". وَقَالَ أَبُو حَازِمٍ عَنْ أَبِي هُرَيْرَةَ عَنِ
النَّبِيِّ صلى الله عليه وسلم " كَلْبَ صَيْدٍ أَوْ مَاشِيَةٍ ".
Allah's Messenger (ﷺ) said, "Whoever keeps a dog, one Qirat of the
reward of his good deeds is deducted daily, unless the dog is used for
guarding a farm or cattle." Abu Huraira (in another narration) said
from the Prophet, "unless it is used for guarding sheep or farms, or
for hunting." Narrated Abu Hazim from Abu Huraira: The Prophet (ﷺ)
said, "A dog for guarding cattle or for hunting."
sahih al-bukhari
I think there no other type of dog use mentioned in ahadith but those three. That's why you need some scholars' statement to know if some other uses of dogs could be measured on this three.