error in wcf method

Question

Hi,

I am getting following error in my code:

error:

'WcfClient.Client.ConsultationClientWCF(ref int)': not all code paths return a value

code:

 
public  retour ConsultationClientWCF( ref int ID_CLIENT)
        {          
            Service1 ser = new Service1();
            ser.ConsultationClient(ID_CLIENT);

            if ( ser.ConsultationClient(ID_CLIENT).Equals(0)){
                retour rt = new retour();              
                rt.succes = 0;
                rt.msgsucces = "opération réeussite";
                return rt;           
            }
                   
            else if (ser.ConsultationClient(ID_CLIENT).Equals(-1)){             
                retour ht = new retour();
                ht.echec = -1;
                ht.msgechec = "Operation échoué";
              return ht;  
            }           
        }