15

I have a ComboBox which I need to use in several places in my application, so I set most of the properties of that ComboBox in ResourceDictionary and use that as a Style where ever I need it.

Style for the ComboBox is:

<Style TargetType="{x:Type ComboBox}" x:Key="ComboBoxBranch"> 
    <Setter Property="ItemsSource" Value="{Binding Branches}"></Setter>
    <Setter Property="DisplayMemberPath" Value="BranchName"></Setter>              
    <Setter Property="SelectedItem" Value="{Binding SelectedBranch}"></Setter>        
</Style>

and I am using it like this in my XAML:

<ComboBox Style="{StaticResource ComboBoxBranch}">
     <i:Interaction.Triggers>
          <i:EventTrigger EventName="SelectionChanged">
             <i:InvokeCommandAction Command="{Binding SelectCustomerCommand}" CommandParameter="{Binding SelectedBranch}" ></i:InvokeCommandAction>
          </i:EventTrigger>
     </i:Interaction.Triggers>
</ComboBox>

I want to move the interaction trigger code as well to ResourceDictionary, so I don't need to write it in all my xamls. Is it possible somehow?

Anatoliy Nikolaev
  • 22,370
  • 15
  • 69
  • 68
Manvinder
  • 4,495
  • 16
  • 53
  • 100
  • http://stackoverflow.com/questions/14986045/wpf-how-to-add-blend-interaction-trigger-to-style-resource – Heena Mar 11 '14 at 10:40

2 Answers2

16

As far as I know, Interaction.Triggers can not be applied in Style, respectively and in a ResourceDictionary. But you can do so, to determine the ComboBox as a resource with x:Shared="False" and reference it for ContentControl like this:

<Window.Resources>
    <ComboBox x:Key="MyComboBox"
              x:Shared="False"
              ItemsSource="{Binding Branches}"
              DisplayMemberPath="BranchName"
              SelectedItem="{Binding SelectedBranch}">

        <i:Interaction.Triggers>
            <i:EventTrigger EventName="SelectionChanged">
                <i:InvokeCommandAction Command="{Binding SelectCustomerCommand}" />
            </i:EventTrigger>
        </i:Interaction.Triggers>
    </ComboBox>
</Window.Resources>

<Grid>
    <ContentControl Name="MyComboBox1"
                    Width="100"
                    Height="30"
                    HorizontalAlignment="Left"
                    Content="{StaticResource MyComboBox}" />

    <ContentControl Name="MyComboBox2"
                    Width="100"
                    Height="30"
                    HorizontalAlignment="Right"
                    Content="{StaticResource MyComboBox}" />
</Grid>

When x:Shared="True" by default then one Style is common to all - in this case, the system swears on the duplicate Content. When x:Shared="False" when is created Style for each element whenever it its request. Quote from MSDN:

When set to false, modifies WPF resource-retrieval behavior so that requests for the attributed resource create a new instance for each request instead of sharing the same instance for all requests.

For more information, please see:

MSDN: x:Shared Attribute

Edit: alternative solution

Here, Mr.Vspivak published a solution that allows you easily set the Interaction.Triggers in Style.

Example:

MainWindow.xaml

<Window x:Class="StylesInteractivity.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"        
        xmlns:ie="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity" 
        xmlns:Core="clr-namespace:Microsoft.Expression.Interactivity.Core;assembly=Microsoft.Expression.Interactions" 
        xmlns:int="clr-namespace:System.Windows.Interactivity" 
        xmlns:si="clr-namespace:StylesInteractivity"
        Title="MainWindow" Height="350" Width="525">

    <Window.Resources>
        <si:ViewModel x:Key="Model" />
    </Window.Resources>

    <Grid>      
        <Grid.ColumnDefinitions>
            <ColumnDefinition />
            <ColumnDefinition />
        </Grid.ColumnDefinitions>

        <TextBlock Grid.Column="1" x:Name="_tblock" 
                   Text="Default" 
                   HorizontalAlignment="Center" 
                   VerticalAlignment="Center" 
                   FontSize="24" 
                   FontWeight="Bold" />

        <ListBox ItemsSource="{Binding Source={StaticResource Model}, Path=DataSource}" 
                 Grid.Column="0"
                 HorizontalAlignment="Center" 
                 VerticalAlignment="Center">

            <ListBox.ItemContainerStyle>
                <Style TargetType="ListBoxItem">
                    <Setter Property="FontSize" Value="24"/>
                    <Setter Property="FontWeight" Value="Bold"/>

                    <Setter Property="int:InteractivityItems.Template">
                        <Setter.Value>
                            <int:InteractivityTemplate>
                                <int:InteractivityItems>
                                    <int:InteractivityItems.Behaviors>
                                        <int:FlipOnHover />
                                    </int:InteractivityItems.Behaviors>

                                    <int:InteractivityItems.Triggers>
                                        <ie:EventTrigger EventName="MouseMove">
                                            <Core:ChangePropertyAction PropertyName="Text"
                                                                       TargetObject="{Binding ElementName=_tblock}"
                                                                       Value="{Binding}" />
                                        </ie:EventTrigger>
                                    </int:InteractivityItems.Triggers>
                                </int:InteractivityItems>
                            </int:InteractivityTemplate>
                        </Setter.Value>
                    </Setter>
                </Style>
            </ListBox.ItemContainerStyle>
        </ListBox>
    </Grid>
</Window>

InteractivityHelper.cs

/// <summary>
/// <see cref="FrameworkTemplate"/> for InteractivityElements instance
/// <remarks>Subclassed for forward compatibility, perhaps one day <see cref="FrameworkTemplate"/> </remarks>
/// <remarks>will not be partially internal</remarks>
/// </summary>
public class InteractivityTemplate : DataTemplate
{

}

/// <summary>
/// Holder for interactivity entries
/// </summary>
public class InteractivityItems : FrameworkElement
{
    private List<Behavior> _behaviors;
    private List<TriggerBase> _triggers;

    /// <summary>
    /// Storage for triggers
    /// </summary>
    public List<TriggerBase> Triggers
    {
        get
        {
            if (_triggers == null)
                _triggers = new List<TriggerBase>();
            return _triggers;
        }
    }

    /// <summary>
    /// Storage for Behaviors
    /// </summary>
    public List<Behavior> Behaviors
    {
        get
        {
            if (_behaviors == null)
                _behaviors = new List<Behavior>();
            return _behaviors;
        }
    }

    #region Template attached property

    public static InteractivityTemplate GetTemplate(DependencyObject obj)
    {
        return (InteractivityTemplate)obj.GetValue(TemplateProperty);
    }

    public static void SetTemplate(DependencyObject obj, InteractivityTemplate value)
    {
        obj.SetValue(TemplateProperty, value);
    }

    public static readonly DependencyProperty TemplateProperty =
        DependencyProperty.RegisterAttached("Template", 
        typeof(InteractivityTemplate), 
        typeof(InteractivityItems),
        new PropertyMetadata(default(InteractivityTemplate), OnTemplateChanged));

    private static void OnTemplateChanged(
        DependencyObject d, 
        DependencyPropertyChangedEventArgs e)
    {
        InteractivityTemplate dt = (InteractivityTemplate)e.NewValue;
#if(!SILVERLIGHT)
        dt.Seal();
#endif
        InteractivityItems ih = (InteractivityItems)dt.LoadContent();
        BehaviorCollection bc = Interaction.GetBehaviors(d);
        TriggerCollection tc = Interaction.GetTriggers(d);

        foreach (Behavior behavior in ih.Behaviors)
            bc.Add(behavior);

        foreach (TriggerBase trigger in ih.Triggers)
            tc.Add(trigger);
    }

    #endregion
}

FlipOnHover.cs

public class FlipOnHover : Behavior<FrameworkElement>
{
    protected override void OnAttached()
    {
        AssociatedObject.MouseEnter += AssociatedObject_MouseEnter;
        AssociatedObject.MouseLeave += AssociatedObject_MouseLeave;
        Transform t = AssociatedObject.RenderTransform;

        AssociatedObject.RenderTransform = new TransformGroup();
        ((TransformGroup)AssociatedObject.RenderTransform).Children.Add(t);
        ((TransformGroup)AssociatedObject.RenderTransform).Children.Add(new ScaleTransform());
        base.OnAttached();
    }

    void AssociatedObject_MouseLeave(object sender, System.Windows.Input.MouseEventArgs e)
    {
        ((ScaleTransform)((TransformGroup)AssociatedObject.RenderTransform).Children[1]).ScaleY = 1;
    }

    void AssociatedObject_MouseEnter(object sender, System.Windows.Input.MouseEventArgs e)
    {
        ((ScaleTransform)((TransformGroup)AssociatedObject.RenderTransform).Children[1]).CenterX = AssociatedObject.ActualWidth / 2;
        ((ScaleTransform)((TransformGroup)AssociatedObject.RenderTransform).Children[1]).CenterY = AssociatedObject.ActualHeight / 2;
        ((ScaleTransform)((TransformGroup)AssociatedObject.RenderTransform).Children[1]).ScaleY=-1;
    }

    protected override void OnDetaching()
    {
        base.OnDetaching();
        AssociatedObject.MouseEnter -= AssociatedObject_MouseEnter;
        AssociatedObject.MouseLeave -= AssociatedObject_MouseLeave;
    }
}

ViewModel.cs

public class ViewModel
{
    private ObservableCollection<String> _dataSource = new ObservableCollection<string>();

    public ViewModel()
    {
        _dataSource.Add("Cat");
        _dataSource.Add("Dog");
        _dataSource.Add("Mouse");
        _dataSource.Add("Owl");
        _dataSource.Add("Rabbit");
    }

    public IEnumerable<string> DataSource
    {
        get { return _dataSource; }
    }
}

For more info, see this link:

Using Interactivity Behaviors and Actions in WPF/Silverlight Styles

Anatoliy Nikolaev
  • 22,370
  • 15
  • 69
  • 68
  • The only way I could get benefit from it if I could use it as Application Resource, window.resources does not make much sense to me here as one Window is having it only once but several windows are going to have this combobox. But I am not able to use it as App.Resources. Please advice. – Manvinder Mar 11 '14 at 10:29
  • @MegaMind: Yes, in this case you can define it in the `App.xaml`. `Window.Resources` it is the same resource dictionary, and his chosen for demonstration purposes only, just test it. – Anatoliy Nikolaev Mar 11 '14 at 10:33
  • 1
    It works. Using content control instead of combobox is very smart move. If possible elaborate the use of ContentControl instead of combobox some more, so it'll help to understand how this thing actually works. Thanks – Manvinder Mar 11 '14 at 11:29
  • @AnatoliyNikolaev i am having multiple controls in my wpf window and i wnat to make interactivity trigger common is it possible – Meer Feb 12 '16 at 05:46
2

I usually work with Silverlight so I'm not sure if the following approach is sensible in WPF: You can pull your xaml into a UserControl, say BranchSelection.xaml for example:

<UserControl x:Class="foobar.BranchSelection">
    <ComboBox 
        ItemsSource="{Binding Branches}"
        DisplayMemberPath="BranchName"
        SelectedItem="{Binding SelectedBranch}">
        <i:Interaction.Triggers>
            <i:EventTrigger EventName="SelectionChanged">
                <i:InvokeCommandAction
                    Command="{Binding SelectCustomerCommand}"
                    CommandParameter="{Binding SelectedBranch}"/>
            </i:EventTrigger>
        </i:Interaction.Triggers>
    </ComboBox>
</UserControl>

And use it like this:

<StackPanel>
    <BranchSelection x:Name="CustomerSelector_1"/>
    <BranchSelection x:Name="CustomerSelector_2"/>
</StackPanel>
Martin
  • 5,714
  • 2
  • 21
  • 41