private async void MainButtonClick(object sender) { bool Birthday = false; ShowLoader(); await Task.Run(() => { UpdateTextBoxes(); Birthday = BirthdayInfo.IsBirthday(ChosenDate); }); HideLoader(); if (AgeInfo.Length == 0) { MessageBox.Show("Your entered date of birth is incorrect! The computed age can not be lower or qual to 0 and higher than 135 years old. Try again!"); } else if (Birthday) { MessageBox.Show("Hey, it`s your birthday today! Congratulations!"); } }