[en] Nuclear transition charge/current density operators are composed according to valence nucleon degrees of freedom. By using boson expansion technique, a microscopic theoretical method (BE method) about the transformation of the fermion density operators into boson density operators is established. Thus, calculations of the nuclear charge/current densities can be carried out in the boson state space by taking advantage of the eigenfunctions of the microscopic IBM. Associated with the formal theories of electron-nucleus scattering and nuclear electromagnetic transition, a microscopic approach, which can be used to study nuclear transition charge/current densities, various form factors, differential cross sections, reduced transition rates, electromagnetic multipole moments, g factors and so on, is built up. The preliminary results based on the microscopic sdIBM-2 has indicated that the physical quantities mentioned before can be described well in the framework of the microscopic approach. The preliminary calculations of spectrum, E2 transition boson structure functions (BSF) and transition charge density from 2₁⁺ to 0₁⁺ in ¹⁹²Os are carried out in terms of the present approach in the frame of the microscopic sd IBM-2. It is found that a reasonable description of these physical quantities has been achieved