In DC microgrids, hierarchical control that is always time-triggered, has been successfully adopted to achieve multiple control objectives with decoupled design at different timescales. Recently, the event-triggered control schemes have been emerged with primary benefit of saving communication resources when compared with conventional time-triggered ones. However, general event-triggered control schemes are in a continuous state, which are not in line with the actual application of digital signal processors. To address this issue, a sampled-data-based event-triggered distributed secondary control strategy is proposed, which updates the control and transmits local information to neighbors only when event triggering condition based on sampling period is violated, and Zeno behavior with infinite number of triggering in a finite time can be excluded as well. The sufficient conditions for the stability of the control strategy are derived by Lyapunov functional method for both fixed and switched communication topologies. Finally, the simulation model is built in MATLAB/Simulink environment to validate the proposed strategy.