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WPF -- it's gotta be easier than I'm making it

I'm having the darndest time figuring this out: say I've got two Button and three TextBlocks. I want either button to trigger a simple Storyboard on ALL TextBlocks. Currently I'm trying to define a generic Textblock style that contains the Storyboard, and then the trigger comes from any Button click. This is the closest I've come but the app crashes on startup...what am I don't wrong here:

<Window.Resources>

<Style TargetType="TextBlock" >
    <Setter Property="Foreground" Value="Blue" />
    <Style.Resources>
        <Storyboard x:Key="TextBlockOpacity" Storyboard.TargetProperty="Opacity">
            <DoubleAnimation From="0" To="1" />
        </Storyboard>
    </Style.Resources>      
</Style>

<Window.Triggers>
    <EventTrigger RoutedEvent="ButtonBase.Click" SourceName="button">
        <BeginStoryboard Storyboard="{StaticResource TextBlockOpacity}"/>
    </EventTrigger>
</Window.Triggers>


<Grid x:Name="LayoutRoot">
    <Button x:Name="button" HorizontalAlignment="Left" Margin="51,54,0,0" VerticalAlignment="Top" Width="96" Height="45" Content="Button"/>

    <TextBlock x:Name="textBlock1" Margin="228,54,172,0" VerticalAlignment="Top" Height="45" FontSize="26.667" Text="TextBlock" TextWrapping="Wrap" />
    <TextBlock x:Name="textBlock2" Margin="228,103,172,0" VerticalAlignment="Top" Height="45" FontSize="26.667" Text="Hello" TextWrapping="Wrap"/>
</Grid>
like image 886
LSTayon Avatar asked Aug 06 '09 12:08

LSTayon


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1 Answers

If you "dedicate" the button to changing the opacity, you could harness its DataContext and animate it. Then simply bind your elements' Opacity to the DataContext:

(I've also refactored your xaml a bit)

<Window x:Class="SomeNamespace.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:System="clr-namespace:System;assembly=mscorlib"
    Title="Window1" Height="300" Width="300">
    <Window.Resources>        
        <Storyboard x:Key="TextBlockOpacity" Storyboard.TargetName="button1" Storyboard.TargetProperty="DataContext" >
            <DoubleAnimation From="0.1" To="1"/>
        </Storyboard>        
        <Style TargetType="TextBlock" >
            <Setter Property="Foreground" Value="Blue" />
            <Setter Property="Background" Value="LightGray" />
            <Setter Property="FontSize" Value="26.667" />
            <Setter Property="TextWrapping" Value="Wrap" />
            <Setter Property="Height" Value="45" />            
            <Setter Property="Opacity" Value="{Binding ElementName=button1, Path=DataContext}"/>
        </Style>
    </Window.Resources>

    <Window.Triggers>
        <EventTrigger RoutedEvent="ButtonBase.Click">
            <BeginStoryboard Storyboard="{StaticResource TextBlockOpacity}" >
            </BeginStoryboard>
        </EventTrigger>

        <EventTrigger RoutedEvent="ListBox.SelectionChanged">
            <BeginStoryboard Storyboard="{StaticResource TextBlockOpacity}" >
            </BeginStoryboard>
        </EventTrigger>
    </Window.Triggers>

    <Grid x:Name="LayoutRoot">
        <Button x:Name="button1" HorizontalAlignment="Left" Margin="51,54,0,0" VerticalAlignment="Top" Width="96" Height="45" Content="Button">
            <Button.DataContext>
                <System:Double>0</System:Double>
            </Button.DataContext>
        </Button>

        <Button x:Name="button2" HorizontalAlignment="Right" Margin="0,54,29,0" VerticalAlignment="Top" Width="96" Height="45" Content="Button"/>

        <ListBox x:Name="listBox1" Height="50" VerticalAlignment="Top">
            <ListBox.Items>
                <System:String>Text1</System:String>
                <System:String>Text2</System:String>
            </ListBox.Items>
        </ListBox>

        <TextBlock x:Name="textBlock1" Margin="51,114,61,0" Text="TextBlock" Height="45" VerticalAlignment="Top" Width="166" />
        <TextBlock x:Name="textBlock2" Margin="51,0,74,42" Text="Hello" Height="45" Width="153" VerticalAlignment="Bottom" />
    </Grid>
</Window>

Also note one thing - this is the approach to use if you want to minimize your code, and make it all happen in xaml. Your approach would anmate the Opacity of the whole Window. That's why in the code above, TextBlocks bind to the button's DataContext, which is itself animated.

It is of course doable without binding to a common value (the DataContext), but then you need to repeat X animations (because you need to set X TargetNames). This approach above is more easily extendable and maintainable.

EDIT

Added another Button and a ListBox for variety :)

like image 82
Kenan E. K. Avatar answered Sep 23 '22 03:09

Kenan E. K.