BooleanKeyFrame.Value Property

Gets or sets the key frame's target value.

Namespace:  System.Windows.Media.Animation
Assembly:  PresentationCore (in PresentationCore.dll)
XMLNS for XAML: http://schemas.microsoft.com/winfx/2006/xaml/presentation, http://schemas.microsoft.com/netfx/2007/xaml/presentation

public bool Value { get; set; }
<object Value="bool" .../>

Property Value

Type: System.Boolean
The key frame's target value, which is the value of this key frame at its specified KeyTime. The default value is false.

Identifier field

ValueProperty

Metadata properties set to true

None

This example shows how to animate the Boolean property value of a Button control by using key frames.

The following example uses the BooleanAnimationUsingKeyFrames class to animate the IsEnabled property of a Button control. All the key frames in this example use an instance of the DiscreteBooleanKeyFrame class. Discrete key frames like DiscreteBooleanKeyFrame create sudden jumps between values, that is, the movement of the animation is jerky.


// Demonstrates a BooleanAnimationUsingKeyFrames. The animation is used to
// animate the IsEnabled property of a button.
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Shapes;
using System.Windows.Media.Animation;
using System.Windows.Media;

namespace Microsoft.Samples.KeyFrameExamples
{
    public class BooleanAnimationUsingKeyFramesExample : Page
    {
        public BooleanAnimationUsingKeyFramesExample()
        {
            Title = "BooleanAnimationUsingKeyFrames Example";
            Background = Brushes.White;
            Margin = new Thickness(20);

            // Create a NameScope for this page so that
            // Storyboards can be used.
            NameScope.SetNameScope(this, new NameScope());

            StackPanel myStackPanel = new StackPanel();
            myStackPanel.Orientation = Orientation.Vertical;
            myStackPanel.Margin = new Thickness(20);

            // Create a TextBlock to introduce the example.
            TextBlock myTextBlock = new TextBlock();
            myTextBlock.Text = "Click the button to animate its IsEnabled property"
                               + " with aBooleanAnimationUsingKeyFrames animation.";
            myStackPanel.Children.Add(myTextBlock);

            // Create the Button that is the target of the animation.
            Button myButton = new Button();
            myButton.Margin = new Thickness(200);
            myButton.Content = "Click Me";

            myStackPanel.Children.Add(myButton);


            // Assign the Button a name so that
            // it can be targeted by a Storyboard.
            this.RegisterName(
                "AnimatedButton", myButton);

            // Create a BooleanAnimationUsingKeyFrames to
            // animate the IsEnabled property of the Button.
            BooleanAnimationUsingKeyFrames booleanAnimation
                = new BooleanAnimationUsingKeyFrames();
            booleanAnimation.Duration = TimeSpan.FromSeconds(4);


            // All the key frames defined below are DiscreteBooleanKeyFrames. 
            // Discrete key frames create sudden "jumps" between values 
            // (no interpolation). Only discrete key frames can be used 
            // for Boolean key frame animations.

            // Value at the beginning is false
            booleanAnimation.KeyFrames.Add(
                new DiscreteBooleanKeyFrame(
                    false, // Target value (KeyValue)
                    KeyTime.FromTimeSpan(TimeSpan.FromSeconds(0.0))) // KeyTime
                );

            // Value becomes true after the first second.
            booleanAnimation.KeyFrames.Add(
                new DiscreteBooleanKeyFrame(
                    true, // Target value (KeyValue)
                    KeyTime.FromTimeSpan(TimeSpan.FromSeconds(1.0))) // KeyTime
                );

            // Value becomes false after the 2nd second.
            booleanAnimation.KeyFrames.Add(
                new DiscreteBooleanKeyFrame(
                    false, // Target value (KeyValue)
                    KeyTime.FromTimeSpan(TimeSpan.FromSeconds(2.0))) // KeyTime
                );

            // Value becomes true after the third second.
            booleanAnimation.KeyFrames.Add(
                new DiscreteBooleanKeyFrame(
                    true, // Target value (KeyValue)
                    KeyTime.FromTimeSpan(TimeSpan.FromSeconds(3.0))) // KeyTime
                );

            // Value becomes false after 3 and half seconds.
            booleanAnimation.KeyFrames.Add(
                new DiscreteBooleanKeyFrame(
                    false, // Target value (KeyValue)
                    KeyTime.FromTimeSpan(TimeSpan.FromSeconds(3.5))) // KeyTime
                );

            // Value becomes true after the fourth second.
            booleanAnimation.KeyFrames.Add(
                new DiscreteBooleanKeyFrame(
                    true, // Target value (KeyValue)
                    KeyTime.FromTimeSpan(TimeSpan.FromSeconds(4.0))) // KeyTime
                );

            // Set the animation to target the IsEnabled property
            // of the object named "AnimatedButton".
            Storyboard.SetTargetName(booleanAnimation, "AnimatedButton");
            Storyboard.SetTargetProperty(
                booleanAnimation, new PropertyPath(Button.IsEnabledProperty));

            // Create a storyboard to apply the animation.
            Storyboard myStoryboard = new Storyboard();
            myStoryboard.Children.Add(booleanAnimation);

            // Start the storyboard when the button is clicked.
            myButton.Click += delegate(object sender, RoutedEventArgs e)
            {
                myStoryboard.Begin(this);
            };

            Content = myStackPanel;
        }

    }
}



<!-- Demonstrates a BooleanAnimationUsingKeyFrames. The animation is used to
     animate the IsEnabled property of a button. -->
<Page 
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  WindowTitle="KeyFrameBoolean Animation Example">


  <StackPanel Orientation="Vertical" Margin="20">

    <TextBlock>
        Click the button to animate its IsEnabled property with a 
        BooleanAnimationUsingKeyFrames animation.
    </TextBlock>

    <Button Name="myAnimatedButton" Margin="200">Click Me
      <Button.Triggers>
        <EventTrigger RoutedEvent="Button.Click">
          <BeginStoryboard>
            <Storyboard>
              <BooleanAnimationUsingKeyFrames 
                Storyboard.TargetName="myAnimatedButton" 
                Storyboard.TargetProperty="IsEnabled"
                Duration="0:0:4" FillBehavior="HoldEnd">

                <!-- All the key frames below are DiscreteBooleanKeyFrames. Discrete key frames create 
                sudden "jumps" between values (no interpolation). Only discrete key frames can be used 
                for Boolean key frame animations. -->
                <DiscreteBooleanKeyFrame Value="False" KeyTime="0:0:0" />
                <DiscreteBooleanKeyFrame Value="True" KeyTime="0:0:1" />
                <DiscreteBooleanKeyFrame Value="False" KeyTime="0:0:2" />
                <DiscreteBooleanKeyFrame Value="True" KeyTime="0:0:3" />
                <DiscreteBooleanKeyFrame Value="False" KeyTime="0:0:3.5" />
                <DiscreteBooleanKeyFrame Value="True" KeyTime="0:0:4" />
              </BooleanAnimationUsingKeyFrames>            
            </Storyboard>
          </BeginStoryboard>
        </EventTrigger>
      </Button.Triggers>
    </Button>
  </StackPanel>
</Page>


For the complete sample, see KeyFrame Animation Sample.

.NET Framework

Supported in: 4, 3.5, 3.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
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