Occasionally, you might need to perform custom logic before or after a map occurs. These should be a rarity, as it's more obvious to do this work outside of AutoMapper. You can create global before/after map actions:

Mapper.Initialize(cfg => {  cfg.CreateMap
    
     ()    .BeforeMap((src, dest) => src.Value = src.Value + 10)    .AfterMap((src, dest) => dest.Name = "John");});
    

Or you can create before/after map callbacks during mapping:

int i = 10;Mapper.Map
    
     (src, opt => {    opt.BeforeMap((src, dest) => src.Value = src.Value + i);    opt.AfterMap((src, dest) => dest.Name = HttpContext.Current.Identity.Name);});
    

The latter configuration is helpful when you need contextual information fed into before/after map actions.