How to use double-click instead click of expander?

Question

I have a Expander in DataGrid.

I want to instead click behavior, but it need to know IsSelected itself.

Then, use double-click expand.

I need a method easily to implement.

Have any idea?

Answer 1

If you want to double-click to expand/collapse the Expander, you could handle its Loaded event, get a reference to the ToggleButton header button and then handle its PreviewMouseLeftButtonDown like this:

private void Expander_Loaded(object sender, RoutedEventArgs e)
{
    Expander expander = sender as Expander;
    ToggleButton tb = FindVisualChild<ToggleButton>(expander);
    if (tb != null)
    {
        tb.PreviewMouseLeftButtonDown += (ss, ee) =>
        {
            ee.Handled = ee.ClickCount < 2;
        };
    }
}

XAML:

<Expander Header="Expand/Collapse..." Loaded="Expander_Loaded">
    <TextBlock>some content...</TextBlock>
</Expander>