Enabling a button in WPF depending on ListBox.SelectedIndex

Question

I have a rather classic UI situation - two ListBoxes named SelectedItems and AvailableItems - the idea being that the items you have already selected live in SelectedItems, while the items that are available for adding to SelectedItems (i.e. every item that isn't already in there) live in AvailableItems.

Also, I have the < and > buttons to move the current selection from one list to the other (in addition to double clicking, which works fine).

Is it possible in WPF to set up a style/trigger to enable or disable the move buttons depending on anything being selected in either ListBox? SelectedItems is on the left side, so the < button will move the selected AvailableItems to that list. However, if no items are selected (AvailableItems.SelectedIndex == -1), I want this button to be disabled (IsEnabled == false) - and the other way around for the other list/button.

Is this possible to do directly in XAML, or do I need to create complex logic in the codebehind to handle it?

if by fun you mean utterly, utterly horrible, the-only-way-to-make-it-worse-would-be-with-regex, then yeah its great fun — Andrew Bullock
– Andrew Bullock, Commented Jun 3, 2010 at 17:01
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– Cranston, Commented May 30, 2013 at 21:56

Karlas · Accepted Answer · 2012-09-18 11:25:55Z

84

Less code solution:

<Button Name="button1" IsEnabled="{Binding ElementName=listBox1, Path=SelectedItems.Count}" />

If count is 0 that seems to map to false, > 0 to true.

answered Sep 18, 2012 at 11:25

Karlas

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2 Comments

Berty Over a year ago

the nice thing about the other answer is, you can use it for 2 lists, both have to have something selected to enable the button.

luka Over a year ago

this is only if the listview has at least one items , the question is enable button when the item was selected.

score 56 · Accepted Answer · 2013-05-31 01:00:35Z

56

Here's your solution.

<Button Name="btn1" >click me    
    <Button.Style>        
        <Style>            
            <Style.Triggers>                
                <DataTrigger 
                     Binding ="{Binding ElementName=list1, Path=SelectedIndex}" 
                     Value="-1">                    
                    <Setter Property="Button.IsEnabled" Value="false"/>                    
                </DataTrigger>                
            </Style.Triggers>            
        </Style>        
    </Button.Style>    
</Button>

edited May 31, 2013 at 1:00

answered Aug 20, 2008 at 14:00

user1228

Comments

Zufar · Accepted Answer · 2023-02-12 10:57:20Z

0

 <Button IsEnabled="{Binding SelectedValue, ElementName=ListName, Mode=OneWay, TargetNullValue=0}" >Remove</Button>

that worked in my case

answered Feb 12, 2023 at 10:57

Zufar

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