Distributed event-triggered secondary control in microgrids has been widely investigated to improve system efficiency. But most of them are based on consecutive triggering condition monitors, which would in turn increase the computation burden of the system. To this end, this article presents distributed self-triggered algorithmic solutions to the frequency restoration control and active power sharing control of islanded microgrids. Different from event-triggered control schemes, in our self-triggered solutions, each distributed generator is equipped with a local algorithm that enables it to pre-compute the next triggering time instant according to the states at the previous one. Our starting point is to design a triggering condition with a novel estimate error. Then, the next triggering time instant is determined by solving a quadratic equation established based on the triggering condition, rather than monitoring the triggering condition consecutively. Theoretical analysis and simulation results show that the proposed distributed self-triggered secondary controllers can highly reduce the communication and computation costs simultaneously.