WPF Listbox remove selection by clicking on blank space

Question

I have a wpf listbox with a custom item template which contains a rectangle. The each item in the listbox can be selected (only one at a time). I w

Answer 1

To assure that only one item is selected put this in the listbox:

SelectionMode="Single"

then for the unselect when clicking somewhere, you can try to check this events

PreviewMouseLeftButtonUp
LostFocus()

Regards,

Answer 2

For The each item in the listbox can be selected (only one at a time).

You can come up with one of followings

1- Disable the item after it is selected.

2- Maintain a list at backend to mark each index selectable or unselectable.

Answer 3

The simple solution is to data bind a property to the ListBox.SelectedItem property and set it to null whenever you want to clear the selection:

<ListBox ItemsSource="{Binding YourItems}" SelectedItem="{Binding SelectedItem}" 
    SelectionMode="Single" />

Then in code, you can just do this to clear the selection:

SelectedItem = null;

And when would you do that? You can attach a handler to the PreviewMouseLeftButtonDown event of the Window, or any other control in your UI. In the handler method, you could do a hit test to see what the item the user clicked on was:

HitTestResult hitTestResult = 
    VisualTreeHelper.HitTest(controlClickedOn, e.GetPosition(controlClickedOn));
Control controlUnderMouse = hitTestResult.VisualHit.GetParentOfType<Control>();

See the VisualTreeHelper.HitTest Method (Visual, Point) for more help with this part.

Then maybe something like this:

if (controlUnderMouse.GetType() != typeof(ListBoxItem)) SelectedItem = null;

Of course, there are many ways to do this, and you'll have to fill in the few blank spots that I left, but you should get the idea.

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EDIT >>>

The generic GetParentOfType method is a custom Extension Method that is defined in a separate class named DependencyObjectExtensions:

public static class DependencyObjectExtensions
{
    public static T GetParentOfType<T>(this DependencyObject element) 
        where T : DependencyObject
    {
        Type type = typeof(T);
        if (element == null) return null;
        DependencyObject parent = VisualTreeHelper.GetParent(element);
        if (parent == null && ((FrameworkElement)element).Parent is DependencyObject) 
            parent = ((FrameworkElement)element).Parent;
        if (parent == null) return null;
        else if (parent.GetType() == type || parent.GetType().IsSubclassOf(type)) 
            return parent as T;
        return GetParentOfType<T>(parent);
    }

    ...
}

Answer 4

Try ensuring your ListBox's background color is 'Transparent'