Question

So I want to set the currently selected button to green background in a listbox while all buttons that are not selected should stay black. How can I do this. View examplecode below.. cant get it working though.

foreach(Button btn in ListBox.Items)
btn.Background = new SolidColorBrush(Colors.Black);
Button clickedButton = sender as Button;
clickedButton.Background = new SolidColorBrush(Colors.Green);

Answer 1

If you want it that way (without Binding and converters) here you go:
(I’m also assuming that only a button is in the listbox item)

for (int i = 0; i < ListBox.Items.Count; i++)
{
    Button currentButton = ListBox.Items[i] as Button;
    if(currentButton != null)
    {
        if (i == ListBox.SelectedIndex)  
            currentButton.Background = new SolidColorBrush(Colors.Green);

        else 
            currentButton.Background = new SolidColorBrush(Colors.Black);
    }
}