Listbox, not getting selected item

Question

I have an WPF form with a listbox and a button on it.

I populate a listbox (tagbox) with the List and then bind this with datasource as below.

private void WeekFood_Load(object sender, EventArgs e)
        {
         List tags = new List() { "A", "B", "C"};
         tagbox.DataSource = tags;
         InitializeComponent();
        }

Then when I click the button, I run the following code

 private void GenSunday_Click(object sender, EventArgs e)
        {
            MessageBox.Show(tagbox.SelectedItems.Count.ToString());            
        }

No matter how many items are selected in the listbox it always returns 0 with tagbox.SelectedItems always being null.

I have tried populating the box by iterating the list with valuemember and displaymember however this also does not fix things.

How is this fixable.

Many thanks in advance

user_13542972 · Answer

In WPF, please use ItemSource property for ListBox and bind the object to it.

Also call the InitializeComponent(); before assigning any data to the controls.

//MainWindow.xaml.cs

        public MainWindow()
        {
            InitializeComponent();

            List tags = new List() { "A", "B", "C" };
            tagBox.ItemsSource = tags;
        }

        private void button_Click(object sender, RoutedEventArgs e)
        {
            MessageBox.Show(tagBox.SelectedItems.Count.ToString());
        }

In MainWindow.xaml

Listbox, not getting selected item

1 Answers