Add group to the list with View only permissions

Add group to the list with  View only (Role definition)- permissions

  webElevated.AllowUnsafeUpdates = true;

                string libGrpName = list.Title + "_ViewOnly";

                SPGroup grp = webElevated.SiteGroups[libGrpName];

SPRoleAssignment roleAssignmentAdmin = new SPRoleAssignment((SPPrincipal)grp);

                SPRoleDefinition roleAdmin = webElevated.RoleDefinitions["View only"];

                roleAssignmentAdmin.RoleDefinitionBindings.Add(roleAdmin);

                list.RoleAssignments.Add(roleAssignmentAdmin);

                list.Update();

                webElevated.AllowUnsafeUpdates = false;