如何：在对象的外边缘上创建发光效果
更新：2007 年 11 月
本主题介绍如何在对象的外边缘上创建发光效果。
示例
您可以使用 OuterGlowBitmapEffect 类在可见对象的周围创建发光效果。此示例演示如何进行下列操作：
使用简单的标记将发光效果应用于对象。
使用 Style 将发光效果应用于一个或多个对象。
使用带有“代码隐藏”的标记将发光效果应用于对象。
使用动画对应用于对象的发光效果的属性进行动画处理。
.gif "说明") 说明： |
|---|
下面的所有示例都只将单一效果应用于对象。若要应用多个效果，请使用 BitmapEffectGroup。有关更多信息，请参见如何：创建多个可视化效果。 |
下面的示例演示如何使用 OuterGlowBitmapEffect 在 TextBox 的外边缘周围创建蓝色发光效果。
<Page xmlns="https://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="https://schemas.microsoft.com/winfx/2006/xaml">
<StackPanel>
<TextBox Width="200">
<TextBox.BitmapEffect>
<!-- <BitmapEffectGroup> would go here if you wanted to apply more
then one effect to the TextBox. However, in this example only
one effect is being applied so BitmapEffectGroup does not need
to be included. -->
<!-- The OuterGlow is blue, extends out 30 pixels, has the
maximum noise possible, and is 40% Opaque. -->
<OuterGlowBitmapEffect GlowColor="Blue" GlowSize="30" Noise="1"
Opacity="0.4" />
</TextBox.BitmapEffect>
</TextBox>
</StackPanel>
</Page>
下图显示了前面的示例所创建的外部发光效果。
.png)
下面的示例演示如何使用 Style 类将 OuterGlowBitmapEffect 应用于页面上获得焦点的任何 TextBox。
<Page xmlns="https://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="https://schemas.microsoft.com/winfx/2006/xaml">
<!-- Resources define Styles for the entire page. -->
<Page.Resources>
<!-- This style applies to any TextBox on the page. -->
<Style TargetType="{x:Type TextBox}">
<Style.Triggers>
<!-- When the TextBox gains focus such as when the cursor appears
in the TextBox, apply the OuterGlowBitmapEffect to the TextBox. -->
<Trigger Property="IsFocused" Value="True">
<Setter Property = "BitmapEffect" >
<Setter.Value>
<!-- The OuterGlow is blue, extends out 30 pixels, has the
maximum noise possible, and is 40% Opaque. -->
<OuterGlowBitmapEffect GlowColor="Blue" GlowSize="30" Noise="1"
Opacity="0.4" />
</Setter.Value>
</Setter>
</Trigger>
</Style.Triggers>
</Style>
</Page.Resources>
<StackPanel>
<!-- The Style defined above applies to this TextBox which creates
an outer glow around the it. -->
<TextBox Name="textBox1" Width="200" />
</StackPanel>
</Page>
下面的示例演示如何使用带有“代码隐藏”的标记将 OuterGlowBitmapEffect 应用于 TextBox。当 TextBox 获得焦点时，发光效果将出现。此示例显示标记。
<Page xmlns="https://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="https://schemas.microsoft.com/winfx/2006/xaml"
x:Class="SDKSample.OuterGlowExample" >
<StackPanel>
<!-- When this TextBox gains focus, a blue glow surrounds it. -->
<TextBox Width="200" GotFocus="OnFocusCreateGlow"></TextBox>
</StackPanel>
</Page>
下面的示例显示对前面标记的事件进行处理的“代码隐藏”。
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Input;
using System.Windows.Media.Effects;
namespace SDKSample
{
public partial class OuterGlowExample : Page
{
// Add OuterGlow effect.
void OnFocusCreateGlow(object sender, RoutedEventArgs args)
{
// Get a reference to the TextBox.
TextBox myTextBox = (TextBox)sender;
// Initialize a new OuterGlowBitmapEffect that will be applied
// to the TextBox.
OuterGlowBitmapEffect myGlowEffect = new OuterGlowBitmapEffect();
// Set the size of the glow to 30 pixels.
myGlowEffect.GlowSize = 30;
// Set the color of the glow to blue.
Color myGlowColor = new Color();
myGlowColor.ScA = 1;
myGlowColor.ScB = 1;
myGlowColor.ScG = 0;
myGlowColor.ScR = 0;
myGlowEffect.GlowColor = myGlowColor;
// Set the noise of the effect to the maximum possible (range 0-1).
myGlowEffect.Noise = 1;
// Set the Opacity of the effect to 40%. Note that the same effect
// could be done by setting the ScA property of the Color to 0.4.
myGlowEffect.Opacity = 0.4;
// Apply the bitmap effect to the TextBox.
myTextBox.BitmapEffect = myGlowEffect;
}
}
}
下面的示例演示如何对 OuterGlowBitmapEffect 的 GlowSize 属性进行动画处理，以便在 TextBox 获得焦点时显示向外发光的动画。
<Page xmlns="https://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="https://schemas.microsoft.com/winfx/2006/xaml" >
<StackPanel>
<TextBox Width="200">
<TextBox.BitmapEffect>
<!-- This BitmapEffect is targeted by the animation. -->
<OuterGlowBitmapEffect x:Name="myOuterGlowBitmapEffect"
GlowColor="Blue" GlowSize="0" />
</TextBox.BitmapEffect>
<TextBox.Triggers>
<EventTrigger RoutedEvent="TextBox.GotFocus">
<BeginStoryboard>
<Storyboard>
<!-- Animate the GlowSize from 0 to 40 over half a second. -->
<DoubleAnimation
Storyboard.TargetName="myOuterGlowBitmapEffect"
Storyboard.TargetProperty="GlowSize"
From="0" To="40" Duration="0:0:0.5" />
</Storyboard>
</BeginStoryboard>
</EventTrigger>
</TextBox.Triggers>
</TextBox>
</StackPanel>
</Page>
有关完整示例，请参见 位图效果库示例。