private void Button_Click(object sender, RoutedEventArgs e)
{
if (Name.Text != "")
{
DialogResult = true;
}
else
{
var da = new DoubleAnimation();
da.From = 1;
da.To = 0;
da.Duration = new TimeSpan(0, 0, 0, 0, 200);
da.AutoReverse = true;
Name.BeginAnimation(TextBox.OpacityProperty, da);
}
}