I am trying to change the values in ListBox 2 based on the item selected in ListBox 1.
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
ListBox2.Items.Clear();
ListBox2.Items.Add("Monday");
}
private void ListBox1_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
switch (ListBox1.SelectedIndex)
{
case 0:
ListBox2.Items.Clear();
ListBox2.Items.Add("Monday");
break;
case 1:
ListBox2.Items.Clear();
ListBox2.Items.Add("Tuesday");
break;
}
}
}
This works if I remove case 0. ListBox2 loads with "Monday" and changes to "Tuesday" when I select index 1 in ListBox1. It remains "Tuesday" even if I select index 0. And gives following error with the above code when I run it:
NullReferenceException: Object reference not set to an instance of an object.
