Why does the object turn black in the Edit Mode? This object looks fine in this mode. It has a shiny material on 2 selected faces.


However, it turns black in this mode. It looks like wire, with hundreds of edges.
You have an extremely large number of faces (and edges, and vertices). If you hit 'A' a few times in edit mode it will toggle orange/black/orange, etc.

Depending on what you intend to use this for, it may be far too many faces.

It is possible that you have a subdivision-surface modifier on this object, and the 'view subdivision' count is too high. Check your Modifiers tab to find out.