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I want to be able to de-select an item in the ListBox if the user clicks the same item again. There is the SelectionChanged event that everyone uses with ListBoxes, but this obviously will not fire when the selection is unchanged.

There is also no Click event, something people recommend. Visual Studio C# 2015 does not contain such event.

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I have tried using MouseLeftButtonDown event, but once the ListBox has been populated with ListBoxItems, this event does not fire anymore. In addition, I thought about attaching Mouse events to the ListBoxItems, but this does not seem practicable, as I would have to attach n number of new events every time I populate the ListBox.

Does anyone have a XAML solution to this inquiry?

Code Doggo
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  • Setting `SelectionMode="Multiple"` enables to selected multiple items, but also to select and deselect items with a single mouse click. – Clemens Jul 05 '17 at 14:18
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    @Clemens the user should not be able to select multiple items, but I appreciate the answer. mm8's answer works as I had wanted. – Code Doggo Jul 05 '17 at 14:22
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    Just in case you don't know that already, `Ctrl+Click` deselects the selected item in single selection mode (and also in extended mode). That's probably also what users of your application may expect. – Clemens Jul 05 '17 at 14:37

2 Answers2

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You could handle the PreviewMouseLeftButtonDown event for the ListBox container as I suggested here.

How to disable deselection of items in ListView?

mm8
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  • It looks like `SelectedIndex` is updated after the call to this event function. Is there anyway to get the currently selected item index from within this function? – Code Doggo Jul 05 '17 at 16:35
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I originally selected mm8's answer, but I later learned that SelectedIndex is not updated during the PreviewMouseLeftButtonDown event, a feature I indirectly was asking for in the question. You actually get the previous, out-of-date SelectedIndex value when using this event.

I found out if you use the MouseLeftButtonUp event, it actually fires, unlike the MouseLeftButtonDown event, and I get the most recent value for the SelectedIndex variable.

For anyone that cares, this is the System.Windows.Controls's ListBox version. I tried using the Systems.Windows.Forms's ListBox implementation, but it does not support multi-lines out of the box, unlike Controls, so I threw away that idea.

tldr

Use MouseLeftButtonUp event.

Code Doggo
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