public async Task SetRichMenuAsync(string userId, string menuName) { var menu = (await _client.GetRichMenuListAsync()).FirstOrDefault(m => m.Name == menuName); if (menu == null) { return; } var currentMenuId = ""; try { currentMenuId = await _client.GetRichMenuIdOfUserAsync(userId); } catch (LineResponseException e) { if (e.StatusCode != System.Net.HttpStatusCode.NotFound) { throw; } } if (menu.RichMenuId == currentMenuId) { return; } await _client.LinkRichMenuToUserAsync(userId, menu.RichMenuId); }