A first-passage-time-distribution (FPTD) approach is developed to investigate the survival and derived properties of a random walker in discrete lattices with a static trap gauged by a general gating mechanism. This approach is effective since the FPTD is directly related to the survival probability distribution of the walker. The random walk is allowed to be undertaken under any potential fields, such as an electric field. We find the gated FPTD can be exactly expressed in terms of its corresponding ungated FPTD in any dimension. Hence, the survival statistics can be calculated. Two gating mechanisms, Poisson and periodic gating, are explicitly considered to calculate their FPTDs, respectively. From the distributions, their mean first passage times (MFPTs) or mean survival times, and mean numbers of visits (MNVs) needed for the walker to become trapped are calculated. Based on the results of these two gating mechanisms, we conclude that the gated MFPT is equal to the sum of the ungated MFPT to the trap starting from the initial site, and the ungated MFPT to the trap starting from the trap multiplied by MNV-1. We argue that this statement founds the basis of approximations to other more complicated gated systems.