How to enlarge a button in Silverlight?

In a Silverlight app, I'd like my buttons to enlarge by a few pixels when the mouse 开发者_StackOverflow社区is hovering over them. I'd also like it to animate to the new size, rather than just suddenly becoming larger. How can I accomplish this in XAML?

Create a ControlTemplate for your button with a storyboard to animate height/width or transform properties, and a trigger to fire the storyboard on MouseEnter event.

Something a bit like this should do the trick.

here is some code.... its a bit lengthy and it uses VisualStates....

<UserControl
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    x:Class="SilverlightApplication1.MainPage"
    Width="640" Height="480">
    <UserControl.Resources>
        <Style x:Key="ButtonStyle1" TargetType="Button">
            <Setter Property="Background" Value="#FF1F3B53"/>
            <Setter Property="Foreground" Value="#FF000000"/>
            <Setter Property="Padding" Value="3"/>
            <Setter Property="BorderThickness" Value="1"/>
            <Setter Property="BorderBrush">
                <Setter.Value>
                    <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
                        <GradientStop Color="#FFA3AEB9" Offset="0"/>
                        <GradientStop Color="#FF8399A9" Offset="0.375"/>
                        <GradientStop Color="#FF718597" Offset="0.375"/>
                        <GradientStop Color="#FF617584" Offset="1"/>
                    </LinearGradientBrush>
                </Setter.Value>
            </Setter>
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="Button">
                        <Grid x:Name="grid" RenderTransformOrigin="0.5,0.5">
                            <Grid.RenderTransform>
                                <TransformGroup>
                                    <ScaleTransform/>
                                    <SkewTransform/>
                                    <RotateTransform/>
                                    <TranslateTransform/>
                                </TransformGroup>
                            </Grid.RenderTransform>
                            <VisualStateManager.VisualStateGroups>
                                <VisualStateGroup x:Name="CommonStates">
                                    <VisualState x:Name="Normal"/>
                                    <VisualState x:Name="MouseOver">
                                        <Storyboard>
                                            <DoubleAnimationUsingKeyFrames Storyboard.TargetName="BackgroundAnimation" Storyboard.TargetProperty="Opacity">
                                                <SplineDoubleKeyFrame KeyTime="0" Value="1"/>
                                            </DoubleAnimationUsingKeyFrames>
                                            <ColorAnimationUsingKeyFrames Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Rectangle.Fill).(GradientBrush.GradientStops)[1].(GradientStop.Color)">
                                                <SplineColorKeyFrame KeyTime="0" Value="#F2FFFFFF"/>
                                            </ColorAnimationUsingKeyFrames>
                                            <ColorAnimationUsingKeyFrames Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Rectangle.Fill).(GradientBrush.GradientStops)[2].(GradientStop.Color)">
                                                <SplineColorKeyFrame KeyTime="0" Value="#CCFFFFFF"/>
                                            </ColorAnimationUsingKeyFrames>
                                            <ColorAnimationUsingKeyFrames Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Rectangle.Fill).(GradientBrush.GradientStops)[3].(GradientStop.Color)">
                                                <SplineColorKeyFrame KeyTime="0" Value="#7FFFFFFF"/>
                                            </ColorAnimationUsingKeyFrames>
                                            <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Duration="00:00:00.0010000" Storyboard.TargetName="grid" Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[0].(ScaleTransform.ScaleX)">
                                                <EasingDoubleKeyFrame KeyTime="00:00:00" Value="1.25"/>
                                            </DoubleAnimationUsingKeyFrames>
                                            <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Duration="00:00:00.0010000" Storyboard.TargetName="grid" Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[0].(ScaleTransform.ScaleY)">
                                                <EasingDoubleKeyFrame KeyTime="00:00:00" Value="1.25"/>
                                            </DoubleAnimationUsingKeyFrames>
                                        </Storyboard>
                                    </VisualState>
                                    <VisualState x:Name="Pressed">
                                        <Storyboard>
                                            <ColorAnimationUsingKeyFrames Storyboard.TargetName="Background" Storyboard.TargetProperty="(Border.Background).(SolidColorBrush.Color)">
                                                <SplineColorKeyFrame KeyTime="0" Value="#FF6DBDD1"/>
                                            </ColorAnimationUsingKeyFrames>
                                            <DoubleAnimationUsingKeyFrames Storyboard.TargetName="BackgroundAnimation" Storyboard.TargetProperty="Opacity">
                                                <SplineDoubleKeyFrame KeyTime="0" Value="1"/>
                                            </DoubleAnimationUsingKeyFrames>
                                            <ColorAnimationUsingKeyFrames Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Rectangle.Fill).(GradientBrush.GradientStops)[0].(GradientStop.Color)">
                                                <SplineColorKeyFrame KeyTime="0" Value="#D8FFFFFF"/>
                                            </ColorAnimationUsingKeyFrames>
                                            <ColorAnimationUsingKeyFrames Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Rectangle.Fill).(GradientBrush.GradientStops)[1].(GradientStop.Color)">
                                                <SplineColorKeyFrame KeyTime="0" Value="#C6FFFFFF"/>
                                            </ColorAnimationUsingKeyFrames>
                                            <ColorAnimationUsingKeyFrames Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Rectangle.Fill).(GradientBrush.GradientStops)[2].(GradientStop.Color)">
                                                <SplineColorKeyFrame KeyTime="0" Value="#8CFFFFFF"/>
                                            </ColorAnimationUsingKeyFrames>
                                            <ColorAnimationUsingKeyFrames Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Rectangle.Fill).(GradientBrush.GradientStops)[3].(GradientStop.Color)">
                                                <SplineColorKeyFrame KeyTime="0" Value="#3FFFFFFF"/>
                                            </ColorAnimationUsingKeyFrames>
                                        </Storyboard>
                                    </VisualState>
                                    <VisualState x:Name="Disabled">
                                        <Storyboard>
                                            <DoubleAnimationUsingKeyFrames Storyboard.TargetName="DisabledVisualElement" Storyboard.TargetProperty="Opacity">
                                                <SplineDoubleKeyFrame KeyTime="0" Value=".55"/>
                                            </DoubleAnimationUsingKeyFrames>
                                        </Storyboard>
                                    </VisualState>
                                </VisualStateGroup>
                                <VisualStateGroup x:Name="FocusStates">
                                    <VisualState x:Name="Focused">
                                        <Storyboard>
                                            <DoubleAnimationUsingKeyFrames Storyboard.TargetName="FocusVisualElement" Storyboard.TargetProperty="Opacity">
                                                <SplineDoubleKeyFrame KeyTime="0" Value="1"/>
                                            </DoubleAnimationUsingKeyFrames>
                                        </Storyboard>
                                    </VisualState>
                                    <VisualState x:Name="Unfocused"/>
                                </VisualStateGroup>
                            </VisualStateManager.VisualStateGroups>
                            <Border x:Name="Background" Background="White" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" CornerRadius="3">
                                <Grid Margin="1" Background="{TemplateBinding Background}">
                                    <Border x:Name="BackgroundAnimation" Opacity="0" Background="#FF448DCA"/>
                                    <Rectangle x:Name="BackgroundGradient">
                                        <Rectangle.Fill>
                                            <LinearGradientBrush EndPoint=".7,1" StartPoint=".7,0">
                                                <GradientStop Color="#FFFFFFFF" Offset="0"/>
                                                <GradientStop Color="#F9FFFFFF" Offset="0.375"/>
                                                <GradientStop Color="#E5FFFFFF" Offset="0.625"/>
                                                <GradientStop Color="#C6FFFFFF" Offset="1"/>
                                            </LinearGradientBrush>
                                        </Rectangle.Fill>
                                    </Rectangle>
                                </Grid>
                            </Border>
                            <ContentPresenter x:Name="contentPresenter" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" Content="{TemplateBinding Content}" ContentTemplate="{TemplateBinding ContentTemplate}"/>
                            <Rectangle x:Name="DisabledVisualElement" Fill="#FFFFFFFF" RadiusX="3" RadiusY="3" IsHitTestVisible="false" Opacity="0"/>
                            <Rectangle x:Name="FocusVisualElement" Stroke="#FF6DBDD1" StrokeThickness="1" RadiusX="2" RadiusY="2" Margin="1" IsHitTestVisible="false" Opacity="0"/>
                        </Grid>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </UserControl.Resources>

    <Grid x:Name="LayoutRoot" Background="White">
        <Button HorizontalAlignment="Center" VerticalAlignment="Center" Width="75" Content="Button" Style="{StaticResource ButtonStyle1}"/>
    </Grid>
</UserControl>

You need to edit the Template for Button and add an animation for the MouseOver state.

1) In Expression Blend 2/3/4, drag and drop a button on the design surface.
2) Right Click the Button "Edit Template" --> "Edit Copy" --> OK.
You are now editing the Button Template.
3) Go the the States Window and Select the "MouseOver" state from the states list. You are now in a storyboard.
4) Change whatever properties you'd like for the MouseOver state.
5) to achieve the nice transition, add a VisualStateTransition. In the states window, add a new Visual Transition (next to "Common States") from "* -> MouseOver". Give that visual transition the duration in seconds you'd like the transition to take.

If you'd like to learn more on Visual States, consider spending 30 minutes watching these "How Do I" videos by Steve White @ http://expression.microsoft.com/en-us/cc643423.aspx