WPF: ListView Selective Double Clicking

Enhancing User Experience: Smart Handling of Double Clicks in ListView

A common component that finds extensive use in WPF is the ListView, which displays a list of items. If you implement the MouseDoubleClick function on the entire ListView a frequent issue occurs when users accidentally trigger actions by double-clicking on areas of the ListView that are not meant to initiate any action, such as the scrollbar or the column headers. To address this, let's explore the VisualTreeHelper.HitTest which can be used to enhance the ListView by making it ignore double clicks on the scrollbar and the header, ensuring that actions are only triggered by double clicks on the items themselves.

The function ListViewFiles_MouseDoubleClick (provided at the end of this post) serves as an event handler for the MouseDoubleClick event of a ListView. It checks where the double click occurred and proceeds only if the click was on an actual list item, enhancing the application's usability by preventing unintended actions.

How It Works

• Identifying the Clicked Item: The function starts by determining the exact location of the double click within the ListView. This is achieved using VisualTreeHelper.HitTest, which returns information about the visual element that was clicked.

• Checking the Click Target: The crucial part of this functionality is to ascertain whether the double click was on a list item, as opposed to a scrollbar or a column header. To do this, the code traverses up the visual tree starting from the clicked element, checking the type of each parent element until it finds either a ListViewItem, a ScrollViewer, or a GridViewColumnHeader. The traversal stops if it encounters a ListViewItem, indicating the click was on an actual item. However, if a ScrollViewer or GridViewColumnHeader is encountered first, the function returns immediately, effectively ignoring the double click.

• Handling the Double Click: Once it's confirmed that the double click was on a ListViewItem, developers can place their custom code to handle the double click event as needed. This could involve opening an item for editing, displaying detailed information, or any other action relevant to the application's context.

/// <summary>
/// The ListView will ignore double clicks if they occur on the scrollbar or the header.
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void ListViewFiles_MouseDoubleClick(object sender, MouseButtonEventArgs e)
{            
    // Get the clicked item within the ListView
    var item = VisualTreeHelper.HitTest((Visual)sender, e.GetPosition((IInputElement)sender));

    if (item != null)
    {
        // Traverse up the visual tree to check if the click is on a scroll bar or column header
        var target = item.VisualHit;
        while (target != null && target is not ListViewItem && target is not ScrollViewer && target is not GridViewColumnHeader)
        {
            target = VisualTreeHelper.GetParent(target);
        }

        if (target is ScrollViewer or GridViewColumnHeader)
        {
            return;
        }
    }

    // Code goes here to handle double click.
}