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How to begin storyboard based on ListBoxItem selection???

Answer 1

+1 A:

I put together something quick to hopefully help you on your way (new default WPF application, MainWindow's DataContext set to itself). I ended up using an IValueConverter to get the Name from the generated XmlLinkedNode out of the SelectedItem of the ListBox, but there should be a more elegant way using XPath statements I'm not familiar with. Basically declare your Storyboard on the ListBoxes Style, not in the Datatemplate:

XAML:

<Window x:Class="WpfApplication1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:WpfApplication1"
        Title="MainWindow" Height="350" Width="525">
    <Window.Resources>
        <XmlDataProvider x:Key="persons"
                         XPath="persons/person"
                         Source="xmldata.xml" />
        <local:SelectionConverter x:Key="selectionConverter" />
    </Window.Resources>

    <Grid>
        <ListBox Background="White" ItemsSource="{Binding Source={StaticResource persons}}" x:Name="lst">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <StackPanel Orientation="Horizontal">
                        <TextBlock Text="{Binding XPath=name}" />
                        <TextBlock Text="{Binding XPath=prop}" />
                    </StackPanel>
                </DataTemplate>
            </ListBox.ItemTemplate>
            <ListBox.Style>
                <Style>
                    <Style.Triggers>
                        <DataTrigger Binding="{Binding ElementName=lst, Path=SelectedItem, Converter={StaticResource selectionConverter}}"
                                     Value="b">
                            <DataTrigger.EnterActions>
                                <BeginStoryboard>
                                    <Storyboard Duration="0:0:1">
                                        <ColorAnimation Storyboard.TargetProperty="(Background).(SolidColorBrush.Color)"
                                                        To="Green" />
                                    </Storyboard>
                                </BeginStoryboard>
                            </DataTrigger.EnterActions>
                            <DataTrigger.ExitActions>
                                <BeginStoryboard>
                                    <Storyboard Duration="0:0:1">
                                        <ColorAnimation Storyboard.TargetProperty="(Background).(SolidColorBrush.Color)"
                                                        To="White" />
                                    </Storyboard>
                                </BeginStoryboard>
                            </DataTrigger.ExitActions>
                        </DataTrigger>
                    </Style.Triggers>
                </Style>
            </ListBox.Style>
        </ListBox>
    </Grid>
</Window>

MainWindow codebehind:

namespace WpfApplication1
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            this.DataContext = this;
        }
    }
}

SelectionConverter.cs

namespace WpfApplication1
{
    public class SelectionConverter : IValueConverter
    {
        #region IValueConverter Members

        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            return (value == null) ? null : (value as XmlLinkedNode).SelectNodes("name")[0].InnerText;
        }

        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            throw new NotImplementedException();
        }

        #endregion
    }
}

Sample data (Add to your project as XML File):

<?xml version="1.0" encoding="utf-8" ?>
<persons>
    <person>
        <name>a</name>
        <prop>3</prop>
    </person>
    <person>
        <name>b</name>
        <prop>3</prop>
    </person>
    <person>
        <name>c</name>
        <prop>3</prop>
    </person>
</persons>

MrDosu 2010-09-30 12:17:09

Thank you for your help. Unfortunatelly, I am geting error "The tag 'SelectionConverter' does not exist in XML namespace, even though I added it.

vladc77 2010-09-30 12:52:38

Did you add the SelectionConverter class to your namespace which you defined in the XAML

MrDosu 2010-09-30 13:01:44

Yes, I copied your converter class and pasted into MainWindow.xaml.cs, then I added namespace - xmlns:local="clr-namespace:WpfApplication1". It is really starnge. It should work. I checked all naming multiple times, but I am getting the same error in VS and Blend

vladc77 2010-09-30 13:32:51

I also added reference to XML - using System.Xml;

vladc77 2010-09-30 13:33:57

I tried to avoid using converter this way: <DataTrigger Binding="{Binding ElementName=lst, XPath=@name}" Value="b">. It is still does not play storyboard.

vladc77 2010-09-30 13:41:37

The Converter class needs to be publically visible in your namespace. Best use Project->Add->Class in Project Explorer and name it accordingly. If you break in the Convert method you can easily look at the type of data that gets passed as SelectedItem.

MrDosu 2010-09-30 14:14:20

I edited to post to relect the project structure clearer. Only usings are missing (Ctrl+. them in).

MrDosu 2010-09-30 14:19:08

Great. Thank you it is working now. Thank you for sharing this approach with me. I am wondering that if it is possible to do the same witout Converter. Something like this - "<DataTrigger Binding="{Binding ElementName=lst, XPath=@name}" Value="b">. " Getting a value of the node and based on it intitiate storyboard running. I need it because I will have more than one value that should trigger the animations to run and also I will need to add other objects behind, such us sub level items of the list box.

vladc77 2010-09-30 16:53:50

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How to begin storyboard based on ListBoxItem selection???

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