Illustrator :: Can Change Color Of All Objects At Once In Complex File?

I have very complex file, with hundreds of paths, shapes, text, outlined text,  etc... It's a brochure with graphs, scematich drawings and text.
 
Last moment, the client like the reverse the colors from (current) Black on white, to all White on dark gray background.
 
Problem is, I can't seem to find easy way to just change the colors, without selecting one by one, every single object. When I selest all and choose white, it start filling paths with solid fill... Editing it wastes allot of my time and I have many pages to do.
 
Is there any way to simple change color of everything at once, just from black to white ? Or do I have to go object by object manually ?