<ListBox
    x:Name="listBox"
    SelectionChanged="listBox_SelectionChanged">
</ListBox>

void listBox_SelectionChanged(object sender, RoutedEventArgs e) {
    // This method is only called when a selection is changed. 
}

However, I need to call a function that executes even if the already selected item in the list box is clicked again (which would make it selected had it not already been).

I tried the Selected event handler but received this error in visual studio:

Error   CS1061  'ListBox' does not contain a definition for 'Selected' and no accessible extension method 'Selected' accepting a first argument of type 'ListBox' could be found (are you missing a using directive or an assembly reference?)

Is there any other event I might be missing?

Thank you.

CodePudding user response：

1. In .xaml (assume ListBox item is Grid)

<ListBox
    x:Name="listBox"
    SelectionChanged="listBox_SelectionChanged">
        <ListBox.ItemTemplate>
                    <DataTemplate>
                        <Grid PreviewMouseDown="listBox_OnPreviewMouseDown">
                            <!-- Content -->
                        </Grid>
                    </DataTemplate>
        </ListBox.ItemTemplate>
</ListBox>

2. In .xaml.cs (assume MyListItemType is the type of the item in ListBox)

private void listBox_OnPreviewMouseDown(object sender, MouseButtonEventArgs e)
{
    var clickedItem = (sender as FrameworkElement)?.DataContext as MyListItemType;
    if (clickedItem != listBox.SelectedItem) return;
    // same item is selected
    // .. 
}

private void listBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
    var clickedItem = (sender as FrameworkElement)?.DataContext as MyListItemType;
    // new item is selected
    // .. 
}

CodePudding user response：

First Example:

    <UniformGrid>
        <ListBox>
            <ListBox.ItemsSource>
                <sys:String>QWERTY</sys:String>
            </ListBox.ItemsSource>
            <ListBox.ItemContainerStyle>
                <Style TargetType="ListBoxItem">
                    <EventSetter Event="PreviewMouseLeftButtonDown"
                                 Handler="OnItemClick"/>
                </Style>
            </ListBox.ItemContainerStyle>
        </ListBox>
        <TextBlock x:Name="tBlock"/>
    </UniformGrid>
</Window>

        private int count = 0;
        private void OnItemClick(object sender, MouseButtonEventArgs e)
        {
            count  ;
            tBlock.Text  = $"{count}: {((ListBoxItem)sender).Content}{Environment.NewLine}";
        }

Second Example:

        <ListBox SelectionChanged="OnSelection"
                 HorizontalContentAlignment="Stretch">
            <ListBox.ItemsSource>
                <sys:String>QWERTY</sys:String>
            </ListBox.ItemsSource>
            <ListBox.ItemTemplate>
                <DataTemplate DataType="{x:Type sys:Char}">
                    <Grid>
                        <TextBlock x:Name="PART_TBlock" Text="{Binding}"/>
                        <Button x:Name="PART_Btn" Content="{Binding}" Click="OnReselection"
                                BorderThickness="0" Background="Transparent"
                                HorizontalContentAlignment="Left"
                                Visibility="Collapsed"/>
                    </Grid>
                    <DataTemplate.Triggers>
                        <DataTrigger Binding="{Binding IsSelected, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ListBoxItem}}}"
                                     Value="True">
                            <Setter TargetName="PART_TBlock" Property="Visibility" Value="Collapsed"/>
                            <Setter TargetName="PART_Btn" Property="Visibility" Value="Visible"/>
                        </DataTrigger>
                    </DataTemplate.Triggers>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>
        <TextBlock x:Name="tBlockReselection"/>
    </UniformGrid>
</Window>

        private void OnSelection(object sender, SelectionChangedEventArgs e)
        {
            tBlockReselection.Text  = $"Selected: {((ListBox)sender).SelectedItem}{Environment.NewLine}";
        }

        private void OnReselection(object sender, RoutedEventArgs e)
        {
            tBlockReselection.Text  = $"Reselected: {((Button)sender).Content}{Environment.NewLine}";
        }

Third Example:

        <ItemsControl HorizontalContentAlignment="Stretch">
            <ItemsControl.ItemsSource>
                <sys:String>QWERTY</sys:String>
            </ItemsControl.ItemsSource>
            <ItemsControl.ItemTemplate>
                <DataTemplate DataType="{x:Type sys:Char}">
                        <Button Content="{Binding}" Click="OnClickselection"
                                HorizontalContentAlignment="Left"/>
                </DataTemplate>
            </ItemsControl.ItemTemplate>
        </ItemsControl>
        <TextBlock x:Name="tBlockClickSelection"/>
    </UniformGrid>
</Window>

        private void OnClickselection(object sender, RoutedEventArgs e)
        {
            tBlockClickSelection.Text  = $"ClickSelection: {((Button)sender).Content}{Environment.NewLine}";
        }