Aruch HaShulchan, The Laws of Tzedakah, 250:10

The authors of the Shulchan Aruch, paragraph 5 wrote that if the poor of the city are many, the rich say that they should beg door-to-door, and the middle class say that they should not beg door-to-door. Rather, their sustenance should be incumbent upon the public according to their wealth. The law agrees with the middle class, because the essence of the obligation of tzedakah is according to one’s wealth. There are places where the custom is to give voluntarily and others where there is a tax and the giving is done according to the giver’s wishes. One who gives according to how they were blessed, it is suitable that they will be further blessed - until here are the Shulchan Aruch’s words. This is all from a responsum of Rashba (chapter 280), and he goes on to say in this vein that the strict law is according to the words of the middle class, etc. Rather, this generation is impoverished, and there is no wealthy, neither in pocket nor in knowledge. In any case, every place must sustain the poor according to the public tzedakah fund and according to the wealth of the community in general. If afterward they beg door-to-door, let them, and each person should give according to their opinion and will, etc - until here are the words of the Rashba. [Translation by Rabbi Bruce Elder. Edited for gender neutrality]