Can not access datagrid.itemsSource in event handler combobox_selectionChanged?

Question

i am developing a wpf application , in which when the user performs selection changed action on a combobox , selection changed event is triggered, but in the event handler when i update datagrid.itemsSource, error is shown to use a new key word to create the object, through break point i have seen that inside the event handler datagrid object itself is null, but it is not null in the MainWindow function. why is it so?

    private void majorkeys_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {           
        minordata.ItemsSource = ReadLibrary.get_minor_records(majorkeys.SelectedValue.ToString(), minorkeys.SelectedValue.ToString());
    }

This is probably because the SelectionChanged event is fired during InitializeComponent, and the `minordata` field has not yet been set. — Clemens, Aug 04 '17 at 07:56

score 0 · Answer 1 · answered Aug 04 '17 at 09:42

Let me answer my own question, the problem was that when the component is initialized, comboBox.selectedIndex changes and hence comboBox_selectionChanged event is triggered at that time my datagrid's itemsSource is not populated, hence it is null. i have solved the problem by checking if the datagrid's itemsSource is null or not. Here is the code,

private void minorkeys_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        if (minordata != null)
        {
            minordata.ItemsSource = ReadLibrary.get_minor_records(majorkeys.SelectedValue.ToString(), minorkeys.SelectedValue.ToString());
        }
    }

yay! :)

Can not access datagrid.itemsSource in event handler combobox_selectionChanged?

1 Answers1