public async void setDataGrid(DataGrid transaction_value) { DataLaundryType laundryType; List <DataLaundryType> listLaundryType = new List <DataLaundryType>(); MessageBox.Show(transaction.getLaundryType()); laundryType = JsonConvert.DeserializeObject <DataLaundryType>(transaction.getLaundryType()); listLaundryType.Add(laundryType); transaction_value.ItemsSource = listLaundryType; }