An analysis of B+ to DK+ and B+ to Dpi+ decays is presented where the D meson is reconstructed in the two-body final states: K+pi-, K+K-, pi+pi- and pi+K-. Using 1.0 fb-1 of LHCb data, measurements of several observables are made including the first
observation of the suppressed mode B+ to DK+, D to pi+K-. CP violation in B+ to DK+ decays is observed with 5.8 sigma significance.
