Get workflow task related item

  SPList list = null;

        

var relativeUrl = SPContext.Current.Web.ServerRelativeUrl.Equals("/") ? string.Empty : web.ServerRelativeUrl;



            try

            {

                list = SPContext.Current.Web.GetList(string.Concat(relativeUrl, "/Lists/", listname));

            }

            catch

            {

                list = SPContext.Current.Web.GetList(string.Concat(relativeUrl, "/", listname));

            }



list .commandesList.GetItemById(int.Parse( currentItem[SPBuiltInFieldId.WorkflowItemId].ToString()));