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In the process of dielectronic recombination, an electron can be captured by a positive ion into doubly excited resonance states. These states can decay by autoionization or by radiative transitions which produce recombination lines. These lines are important to estimate the element abundances as well as the electron temperatures in planetary nebulae. The present paper reports a theoretical study by the R-matrix method for such processes of C2+ ions in planetary nebulae, which produce recombination lines ?5114 ?(4f'?3d'), ?4965 ?(3d'?3p'), ?4619 ?(4f'?3d') and ?8794 ?(3d'?3p'). Our study is based on three sets of target orbitals, through which we elucidate the electron correlation and static polarization effects in the dielectronic recombination processes. The calculated energy level positions are used to indicate the degrees of our calculation convergence; especially those based on the set of target orbitals including the electron correlation and static polarization effects agree well with the experimental data within about 4%. For such recombination processes, the recommended radiative transition rates, autoionization rates and net recombination rate coefficients are also provided. We anticipate that the accuracy of our recommended recombination rate coefficients for the whole four dielectronic lines is about 7% within our theoretical model.