  We develop the canonical theory of gravitational collapse in 2+1 dimensions
with a negative cosmological constant and obtain exact solutions of the
Wheeler--DeWitt equation regularized on a lattice. We employ these solutions to
derive the Hawking radiation from black holes formed in all models of dust
collapse. We obtain an (approximate) Planck spectrum near the horizon
characterized by the Hawking temperature $T_{\mathrm H}=\hbar\sqrt{G\Lambda
M}/2\pi$, where $M$ is the mass of a black hole that is presumed to form at the
center of the collapsing matter cloud and $-\Lambda$ is the cosmological
constant. Our solutions to the Wheeler-DeWitt equation are exact, so we are
able to reliably compute the greybody factors that result from going beyond the
near horizon region.
