Поместить кнопки в контейнер и менять статус видимости у контейнера:
<Button Content="Ok" HorizontalAlignment="Left" VerticalAlignment="Top"
Width="75" Margin="0,75,0,0"
Click="Button_Click"
/>
<WrapPanel Name="Buttons" Orientation="Horizontal">
<Button Name="Button1" Content="Button" HorizontalAlignment="Left"
VerticalAlignment="Top" Width="75"
/>
<Button Name="Button2" Content="Button" HorizontalAlignment="Left"
VerticalAlignment="Top" Width="75"
/>
<Button Name="Button3" Content="Button" HorizontalAlignment="Left"
VerticalAlignment="Top" Width="75"
/>
<Button Name="Button4" Content="Button" HorizontalAlignment="Left"
VerticalAlignment="Top" Width="75"
/>
</WrapPanel>
private void Button_Click(object sender, RoutedEventArgs e)
{
Buttons.Visibility = Visibility.Hidden; // Visibility.Visible
/*
if (Buttons.Visibility == Visibility.Hidden)
{
Buttons.Visibility = Visibility.Visible;
}
else
{
Buttons.Visibility = Visibility.Hidden;
}
*/
}