I'm looking for the way to code-behind launch an animation on a control contained in an ControlTemplate.
In my app I have custom templated buttons (playing menu role) created from an ObservableCollection :
MainMenuViewModel :
/// <summary>
/// Menu items list
/// </summary>
private ObservableCollection<MenuItem> _items;
....
/// <summary>
/// Menu items list property
/// </summary>
public ObservableCollection<MenuItem> Items
{
get { return _items; }
set { _items = value; }
}
MainMenuView :
<UserControl x:Class="OfficeTourismeBrantome.Views.MainMenuView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d"
d:DesignHeight="800" d:DesignWidth="300">
<UserControl.Resources>
<Style x:Key="MenuItemButtonStyle" TargetType="Button">
<Setter Property="FontSize" Value="60" />
<Setter Property="FontFamily" Value="Segoe" />
<Setter Property="FontWeight" Value="UltraLight" />
<Setter Property="Foreground" Value="#FFEBEDEA" />
<!--<Setter Property="Height" Value="{Binding MenuLayout.MenuItemSize.Height}" />-->
<Setter Property="HorizontalContentAlignment" Value="Right" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Button}">
<ControlTemplate.Triggers>
<EventTrigger RoutedEvent="Button.Click">
<EventTrigger.Actions>
<BeginStoryboard>
<Storyboard Name="themeSelectionAnimation">
<DoubleAnimation
Storyboard.TargetName="coloredRectangle"
Storyboard.TargetProperty="Width"
From="30.0"
To="250.0"
Duration="0:0:0.3" />
</Storyboard>
</BeginStoryboard>
</EventTrigger.Actions>
</EventTrigger>
</ControlTemplate.Triggers>
<Canvas HorizontalAlignment="Stretch" ClipToBounds="False" >
<ContentPresenter Canvas.Left="{Binding MenuLayout.MenuItemLeftMargin}" HorizontalAlignment="Center"
VerticalAlignment="Center" Canvas.ZIndex="1"/>
<TextBlock
Text="{Binding SecondaryText}"
Canvas.Top="50"
Canvas.Left="10"
FontSize="30"
FontWeight="ExtraLight"
FontStyle="Italic"
Canvas.ZIndex="1"
/>
<Rectangle
Canvas.Top="30"
Canvas.Left="10"
Name="coloredRectangle"
Width="30"
Height="10"
Canvas.ZIndex="0"
Fill="{Binding Color}"/>
</Canvas>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Storyboard x:Key="themeUnselectionAnimation">
<DoubleAnimation
Storyboard.TargetProperty="Width"
From="250.0"
To="30.0"
Duration="0:0:0.15" />
</Storyboard>
</UserControl.Resources>
<ItemsControl Name="menuButtonContainer" ItemsSource="{Binding Items}" Margin="{Binding MenuLayout.MenuMargin}">
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel Orientation="Vertical" />
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
<ItemsControl.ItemTemplate>
<DataTemplate>
<Button
Style="{StaticResource ResourceKey=MenuItemButtonStyle}"
Margin="{Binding ElementName=menuButtonContainer,
Path=DataContext.MenuLayout.MenuItemMargin}"
Height="{Binding ElementName=menuButtonContainer,
Path=DataContext.MenuLayout.MenuItemSize.Height}"
Content="{Binding Text}"
Command="{Binding ElementName=menuButtonContainer,
Path=DataContext.ChangeThemeCommand}"
CommandParameter="{Binding Id}"
/>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</UserControl>
As you can see in the code above, I got an animation automatically triggered on button click. I want to play it reverse when another button in the collection is clicked (another menu entry is selected). The animation to play is the one called themeUnselectionAnimation.
First question : is there a way to do it only in XAML? I'm not sure as another button need to be pressed to trigger it.
Below is what I thought :
- In the
Button(which is my menu item) command action, send a message to let subscribers that menu item is changing. - Register to it in
MainMenuViewcode-behind. - Launch animation from there.
My problem so far is to set the target control for the animation. To do that, I need to find the Rectangle named coloredRectangle in ControlTemplate. How to do that ?
Here below is my code corresponding to above steps :
Step 1 : send message (I'm using MVVM Light framework)
/// <summary>
/// Delegates that handles theme change process and tasks
/// </summary>
/// <param name="themeId">the new active theme</param>
private void ChangeTheme(int themeId)
{
// Set current active theme as inactive, if one is selected.
// Exception use because of Single implementation that throw an InvalidOperationException if not item is found
try
{
MenuItem currentTheme = Items.Single(x => x.IsActive == true);
// Check if this is current theme. If it is, we do nothing.
if(currentTheme.Id == themeId)
return;
// If current theme is set and new theme id is not the same, disable the old one
currentTheme.IsActive = false;
// Set new theme as active
Items.Single(x => x.Id == themeId).IsActive = true;
// Finally, launch unselection animation
// Send message and register to it in view code behind
// Create inner message
ThemeChangeNotification innerMessage = new ThemeChangeNotification();
innerMessage.NewThemeId = themeId;
innerMessage.OldThemeId = currentTheme.Id;
NotificationMessage<ThemeChangeNotification> message =
new NotificationMessage<ThemeChangeNotification>(innerMessage, "");
// Send message
Messenger.Default.Send(message);
}
catch (InvalidOperationException exception)
{
// Set first theme selection as active
Items.Single(x => x.Id == themeId).IsActive = true;
}
}
Step 2 : Register to message
Messenger.Default.Register<NotificationMessage<ThemeChangeNotification>>(this, ChangeThemeAnimation);
Step 3 : reach Button from index/id and launch animation (not working)
/// <summary>
/// Theme change message delegate
/// </summary>
/// <param name="e">The ThemeChangeNotification message</param>
private void ChangeThemeAnimation(NotificationMessage<ThemeChangeNotification> message)
{
var buttonTheme = menuButtonContainer.ItemContainerGenerator.ContainerFromIndex(message.Content.OldThemeId) as FrameworkElement;
var rectangle = buttonTheme.FindName("coloredRectangle") as Rectangle;
Storyboard sb = this.FindResource("themeUnselectionAnimation") as Storyboard;
Storyboard.SetTarget(sb, rectangle);
sb.Begin();
}
Thank you very much for your answers !
