private async void SendButton_Click(object sender, RoutedEventArgs e) { var button = sender as Button; var text = button.Content.ToString(); if (SendVerifyCodeCommand?.CanExecute(null) == true) { SendVerifyCodeCommand?.Execute(null); } button.IsEnabled = false; for (int i = 90 - 1; i >= 0; i--) { button.Content = $"{i} s"; await Task.Delay(TimeSpan.FromSeconds(1)); } button.IsEnabled = true; button.Content = text; }