Interaction Triggers in Style in ResourceDictionary WPF
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?
Solution 1:
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 instancefor 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
Solution 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>