using FluentValidation; namespace InternshipSystem.Api.Queries { public class CourseForm { public long? Id { get; set; } public string Name { get; set; } public string NameEng { get; set; } public class Validator : AbstractValidator { public Validator() { RuleFor(c => c.Id).NotNull() .When(c => string.IsNullOrWhiteSpace(c.Name)); RuleFor(c => c.Name).NotEmpty() .When(c => !c.Id.HasValue); } } } }