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DiscreteStringKeyFrame Class

Animates from the String value of the previous key frame to its own Value using discrete interpolation.

Namespace: System.Windows.Media.Animation
Assembly: PresentationCore (in presentationcore.dll)
XML Namespace:  http://schemas.microsoft.com/winfx/2006/xaml/presentation

public class DiscreteStringKeyFrame : StringKeyFrame
public class DiscreteStringKeyFrame extends StringKeyFrame
public class DiscreteStringKeyFrame extends StringKeyFrame
<DiscreteStringKeyFrame .../>

This class is used as part of a StringKeyFrameCollection in conjunction with a StringAnimationUsingKeyFrames to animate a String property value along a set of key frames.

A key frame defines a segment of the StringAnimationUsingKeyFrames to which it belongs. Each key frame has a target Value and a KeyTime. The KeyTime specifies the time at which the key frame's Value should be reached. A key frame animates from the target value of the previous key frame to its own target value. It starts when the previous key frame ends and ends when its own key time is reached.

Discrete key frames like DiscreteStringKeyFrame create sudden "jumps" between values (no Interpolation). In other words, the animated property does not change until the key frame's key time is reached at which point the animated property goes suddenly to the target value.

This example shows how to animate a string, which in this example is the Content property of a Button control, by using key frames.

The following example uses the StringAnimationUsingKeyFrames class to animate the Content property of a Button.

All the key frames in this example use an instance of the DiscreteStringKeyFrame class because a string animation that is created with key frames can only use discrete key frames. Discrete key frames like DiscreteStringKeyFrame create sudden jumps between values, that is, changes to the animation occur quickly and are not subtle.

<!-- Demonstrates the StringAnimationUsingKeyFrames class. A StringAnimationUsingKeyFrames is used to
   animate the TextContent property of a Text element. -->
<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  x:Class="Microsoft.Samples.KeyFrameExamples.StringAnimationUsingKeyFramesExample"
  Name="myRootElement"
  WindowTitle="StringAnimationUsingKeyFrames Example">

  <StackPanel HorizontalAlignment="Center">
    <Button Name="myAnimatedButton" Margin="200"
      FontSize="16pt" FontFamily="Verdana">Some Text
      <Button.Triggers>
        <EventTrigger RoutedEvent="Button.Click">
          <BeginStoryboard>
            <Storyboard>
              <StringAnimationUsingKeyFrames 
                Storyboard.TargetName="myAnimatedButton" Storyboard.TargetProperty="(Button.Content)"
                Duration="0:0:8" FillBehavior="HoldEnd">

                <!-- All the key frames below are DiscreteStringKeyFrames. Discrete key frames create 
                sudden "jumps" between values (no interpolation). Only discrete key frames can be used 
                for String key frame animations. -->
                <DiscreteStringKeyFrame Value="" KeyTime="0:0:0" />
                <DiscreteStringKeyFrame Value="A" KeyTime="0:0:1" />
                <DiscreteStringKeyFrame Value="An" KeyTime="0:0:1.5" />
                <DiscreteStringKeyFrame Value="Ani" KeyTime="0:0:2" />
                <DiscreteStringKeyFrame Value="Anim" KeyTime="0:0:2.5" />
                <DiscreteStringKeyFrame Value="Anima" KeyTime="0:0:3" />
                <DiscreteStringKeyFrame Value="Animat" KeyTime="0:0:3.5" />
                <DiscreteStringKeyFrame Value="Animate" KeyTime="0:0:4" />
                <DiscreteStringKeyFrame Value="Animated" KeyTime="0:0:4.5" />
                <DiscreteStringKeyFrame Value="Animated " KeyTime="0:0:5" />
                <DiscreteStringKeyFrame Value="Animated T" KeyTime="0:0:5.5" />
                <DiscreteStringKeyFrame Value="Animated Te" KeyTime="0:0:6" />
                <DiscreteStringKeyFrame Value="Animated Tex" KeyTime="0:0:6.5" />
                <DiscreteStringKeyFrame Value="Animated Text" KeyTime="0:0:7" />
              </StringAnimationUsingKeyFrames>              
            </Storyboard>
          </BeginStoryboard>
        </EventTrigger> 
      </Button.Triggers>
    </Button>
  </StackPanel>
</Page>

For the complete sample, see KeyFrame Animation Sample.

System.Object
   System.Windows.Threading.DispatcherObject
     System.Windows.DependencyObject
       System.Windows.Freezable
         System.Windows.Media.Animation.StringKeyFrame
          System.Windows.Media.Animation.DiscreteStringKeyFrame
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0
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