public void AjouterClient(Client p_client) { if (p_client is null) { throw new ArgumentNullException(nameof(p_client)); } List <ClientJsonDTO> clientsDTO = this.ListerClientsDTO(); if (clientsDTO.Any(c => c.ClientId == p_client.ClientId)) { throw new InvalidOperationException(); } ClientJsonDTO clientDTO = new ClientJsonDTO(p_client); clientsDTO.Add(clientDTO); this.SauvegarderDepot(clientsDTO); }