Using all types of weapons?

I just started and am currently a necro/mesmer. I like my build except the weapons for these two classes suck. Can i still use other weapons? Does it reduce the damage? I've been using a bow and it seems to hit for the full amount of damage. Is it possible for me to use a bow to full effect even though i'm not a ranger?

You can use any weapon as long as you meet any requirements it has.

Rangers can use staffs, Warriors can use truncheons, and Elementalists can use hammers. It's not suggested, but I'm trying to give an example.

You can use any weapon you want. The extra effects that rely on certain attributes won't work unless you have that attribute, but the base damage is the same for any character.

At early levels, you can generally use any weapon you come across, as they'll have no requirements to use. Later on in the game, you'll be less effective with weapons for different classes, as the weapons will do very little damage if you don't have the required attribute level listed on the weapon. For instance, you can use a 7-10 bow with no Marksmanship requirement as well as any ranger, but you won't do all that much damage with a 10-17 bow with 5 marksmanship required, since you're unable to put points into marksmanship with a N/Me.