2013- current user informations

Hi everyone, 

how can i get the current user's manager's phone information. 

i select the current user id as; 

public Guid workflowId = default(System.Guid);
        public SPWorkflowActivationProperties workflowProperties = new SPWorkflowActivationProperties();

        private void onWorkflowActivated1_Invoked(object sender, ExternalDataEventArgs e)
        {
           
            SPWeb web = workflowProperties.Web;

            SPUser spuser = this.workflowProperties.OriginatorUser;

            string strusername = spuser.Name;
            string strid = spuser.LoginName;

            SPListItem lisitem= workflowProperties.Item;

            if (lisitem["Full Name"] == null)
            {
                listitem["Full Name"] = strid;
                listitem.Update();
            }

but i couldnt find a way to reach manager 's phone information.