  The theoretical approach developed here treats uniformly the direct and
indirect mechanisms of dissociative recombination (DR) in a diatomic ion. The
present theory is based on electron scattering calculations performed at
several internuclear distances in the molecule. It is easy to implement becaus
there is no need to separately evaluate couplings and the bound dissociative
states of the neutral molecule. The theory can be applied to molecular ions
with or without electronic resonances at low energies. The approach is applied
to compute the DR cross section in electron-CH$^+$ collisions. The computed
cross section agrees generally well with recent state-resolved data from a
cryogenic storage-ring experiment, which validates the approach.
