您需要将MappingConfiguration提供程序传递给ProjectTo调用.

You need to pass the MappingConfiguration provider to the ProjectTo call.

public async Task<FreelancerProfileViewModel> GetFreelancerProfile()
{
    var id = Guid.Parse(_identity.GetUserId());
    var model = await _freelancerProfiles
        .AsNoTracking()
        .Where(_ => _.User.Id == id)
        .ProjectTo<FreelancerProfileViewModel>(_mapper.Configuration)
        .FirstAsync();

 //  var viewmodel =  _mapper.Map<FreelancerProfileViewModel>(model);

    return model;
}