IM_NEW/GroupService.WebApi/Controllers/GroupInvitation/GroupInvitationRequest.cs

using FluentValidation;

namespace GroupService.WebApi.Controllers.GroupInvitation
{
    public class GroupInvitationRequest
    {
        public Guid GroupId { get; set; }
        public Guid UserId { get; set; }
    }

    public class GroupInvitationRequestValidator : AbstractValidator<GroupInvitationRequest>
    {
        public GroupInvitationRequestValidator()
        {
            RuleFor(r => r.UserId)
                .NotNull()
                .NotEmpty();

            RuleFor(r => r.GroupId)
                .NotEmpty()
                .NotNull();
        }
    }
}