我有一个组合框，在Silverlight 2.0中，我希望它在用户鼠标悬停在切换按钮上时打开，然后在用户鼠标离开时关闭。默认行为是单击。
这是我的风格代码（抱歉太长了）：
<Style x:Key="HelpComboBoxStyle" TargetType="ComboBox">
<Setter Property="Padding" Value="0,0,0,0"/>
<Setter Property="Background" Value="#FF1F3B53"/>
<Setter Property="HorizontalContentAlignment" Value="Left"/>
<Setter Property="BorderThickness" Value="1"/>
<Setter Property="TabNavigation" Value="Once"/>
<Setter Property="BorderBrush" Value="#104F9B"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="ComboBox">
<Grid>
<Grid.Resources>
<Style TargetType="ToggleButton" x:Name="comboToggleStyle">
<Setter Property="BorderBrush" Value="#104F9B"/>
<Setter Property="BorderThickness" Value="1"/>
<Setter Property="Padding" Value="3"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="ToggleButton">
<Grid>
<vsm:VisualStateManager.VisualStateGroups>
<vsm:VisualStateGroup x:Name="CommonStates">
<vsm:VisualStateGroup.Transitions>
<vsm:VisualTransition GeneratedDuration="00:00:00.1" To="MouseOver"/>
<vsm:VisualTransition GeneratedDuration="00:00:00.1" To="Pressed"/>
</vsm:VisualStateGroup.Transitions>
<vsm:VisualState x:Name="Normal"/>
<vsm:VisualState x:Name="MouseOver">
<Storyboard>
<ObjectAnimationUsingKeyFrames Duration="00:00:00" Storyboard.TargetName="PopupBorder" Storyboard.TargetProperty="(UIElement.Visibility)">
<DiscreteObjectKeyFrame KeyTime="00:00:00">
<DiscreteObjectKeyFrame.Value>
<Visibility>Visible</Visibility>
</DiscreteObjectKeyFrame.Value>
</DiscreteObjectKeyFrame>
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</vsm:VisualState>
<vsm:VisualState x:Name="Pressed">
<Storyboard>
<DoubleAnimationUsingKeyFrames Storyboard.TargetName="BackgroundOverlay2" Storyboard.TargetProperty="Opacity">
<SplineDoubleKeyFrame KeyTime="0" Value="1"/>
</DoubleAnimationUsingKeyFrames>
<DoubleAnimationUsingKeyFrames Storyboard.TargetName="Highlight" Storyboard.TargetProperty="(UIElement.Opacity)">
<SplineDoubleKeyFrame KeyTime="0" Value="1"/>
</DoubleAnimationUsingKeyFrames>
<ColorAnimationUsingKeyFrames Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[1].(GradientStop.Color)">
<SplineColorKeyFrame KeyTime="0" Value="#E5FFFFFF"/>
</ColorAnimationUsingKeyFrames>
<ColorAnimationUsingKeyFrames Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[2].(GradientStop.Color)">
<SplineColorKeyFrame KeyTime="0" Value="#BCFFFFFF"/>
</ColorAnimationUsingKeyFrames>
<ColorAnimationUsingKeyFrames Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[3].(GradientStop.Color)">
<SplineColorKeyFrame KeyTime="0" Value="#6BFFFFFF"/>
</ColorAnimationUsingKeyFrames>
<ColorAnimationUsingKeyFrames Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[0].(GradientStop.Color)">
<SplineColorKeyFrame KeyTime="0" Value="#F2FFFFFF"/>
</ColorAnimationUsingKeyFrames>
</Storyboard>
</vsm:VisualState>
<vsm:VisualState x:Name="Disabled">
<Storyboard>
<DoubleAnimationUsingKeyFrames Storyboard.TargetName="DisabledVisualElement" Storyboard.TargetProperty="(UIElement.Opacity)">
<SplineDoubleKeyFrame KeyTime="0" Value="1"/>
</DoubleAnimationUsingKeyFrames>
</Storyboard>
</vsm:VisualState>
</vsm:VisualStateGroup>
<vsm:VisualStateGroup x:Name="CheckStates"/>
<vsm:VisualStateGroup x:Name="FocusStates"/>
</vsm:VisualStateManager.VisualStateGroups>
<Rectangle x:Name="Background" Fill="{TemplateBinding Background}" Stroke="{TemplateBinding BorderBrush}" StrokeThickness="{TemplateBinding BorderThickness}" />
<Rectangle x:Name="BackgroundOverlay" Opacity="0" Fill="#FF448DCA" Stroke="#00000000" StrokeThickness="{TemplateBinding BorderThickness}" />
<Rectangle x:Name="BackgroundOverlay2" Opacity="0" Fill="#FF448DCA" Stroke="#00000000" StrokeThickness="{TemplateBinding BorderThickness}" />
<Rectangle Margin="{TemplateBinding BorderThickness}" x:Name="BackgroundGradient" Stroke="#FFFFFFFF" StrokeThickness="2" >
<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>
<Rectangle x:Name="BackgroundOverlay3" Opacity="0" Fill="#FF448DCA" Stroke="#00000000" StrokeThickness="{TemplateBinding BorderThickness}"/>
<Rectangle Margin="{TemplateBinding BorderThickness}" x:Name="BackgroundGradient2" Opacity="0" Stroke="#FFFFFFFF" StrokeThickness="2" >
<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>
<Rectangle Margin="{TemplateBinding BorderThickness}" x:Name="Highlight" IsHitTestVisible="false" Opacity="0" Stroke="#FF45D6FA" StrokeThickness="2" />
<ContentPresenter HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" x:Name="contentPresenter" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" Content="{TemplateBinding Content}" ContentTemplate="{TemplateBinding ContentTemplate}"/>
<Rectangle x:Name="DisabledVisualElement" IsHitTestVisible="false" Opacity="0" Fill="#A5FFFFFF" />
<Rectangle x:Name="FocusVisualElement" IsHitTestVisible="false" Visibility="Collapsed" Stroke="#FF45D6FA" StrokeThickness="2" />
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Grid.Resources>
<vsm:VisualStateManager.VisualStateGroups>
<vsm:VisualStateGroup x:Name="CommonStates">
<vsm:VisualStateGroup.Transitions>
<vsm:VisualTransition GeneratedDuration="00:00:00.1"/>
<vsm:VisualTransition From="MouseOver" GeneratedDuration="00:00:00.1000000" To="Normal"/>
</vsm:VisualStateGroup.Transitions>
<vsm:VisualState x:Name="Normal"/>
<vsm:VisualState x:Name="MouseOver"/>
<vsm:VisualState x:Name="Disabled">
<Storyboard>
<DoubleAnimationUsingKeyFrames Storyboard.TargetName="DisabledVisualElement" Storyboard.TargetProperty="(UIElement.Opacity)">
<SplineDoubleKeyFrame KeyTime="00:00:00" Value="1"/>
</DoubleAnimationUsingKeyFrames>
</Storyboard>
</vsm:VisualState>
</vsm:VisualStateGroup>
<vsm:VisualStateGroup x:Name="FocusStates">
<vsm:VisualState x:Name="Focused">
<Storyboard>
<DoubleAnimationUsingKeyFrames Storyboard.TargetName="FocusVisualElement" Storyboard.TargetProperty="(UIElement.Opacity)">
<SplineDoubleKeyFrame KeyTime="00:00:00" Value="1"/>
</DoubleAnimationUsingKeyFrames>
</Storyboard>
</vsm:VisualState>
<vsm:VisualState x:Name="Unfocused"/>
<vsm:VisualState x:Name="FocusedDropDown">
<Storyboard>
<ObjectAnimationUsingKeyFrames Duration="00:00:00" Storyboard.TargetName="PopupBorder" Storyboard.TargetProperty="(UIElement.Visibility)">
<DiscreteObjectKeyFrame KeyTime="00:00:00">
<DiscreteObjectKeyFrame.Value>
<Visibility>Visible</Visibility>
</DiscreteObjectKeyFrame.Value>
</DiscreteObjectKeyFrame>
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</vsm:VisualState>
</vsm:VisualStateGroup>
</vsm:VisualStateManager.VisualStateGroups>
<Border x:Name="ContentPresenterBorder">
<Grid>
<ToggleButton HorizontalAlignment="Stretch" Margin="0" x:Name="DropDownToggle" Background="white" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" HorizontalContentAlignment="Right">
<Path Height="8" HorizontalAlignment="Center" Margin="0,0,0,0" x:Name="BtnArrow" Width="10" Stretch="Uniform" Data="F1 M 301.14,-189.041L 311.57,-189.041L 306.355,-182.942L 301.14,-189.041 Z ">
<Path.Fill>
<SolidColorBrush Color="#104F9B" x:Name="BtnArrowColor"/>
</Path.Fill>
</Path>
</ToggleButton>
<ContentPresenter Visibility="Collapsed" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" x:Name="ContentPresenter" VerticalAlignment="{TemplateBinding VerticalContentAlignment}">
</ContentPresenter>
</Grid>
</Border>
<Rectangle x:Name="DisabledVisualElement" IsHitTestVisible="false" Opacity="0" Fill="#A5FFFFFF" RadiusX="3" RadiusY="3"/>
<Rectangle x:Name="FocusVisualElement" IsHitTestVisible="false" Opacity="0" Stroke="#FF45D6FA" StrokeThickness="1" RadiusX="3" RadiusY="3"/>
<Popup x:Name="Popup">
<Popup.RenderTransform>
<TranslateTransform X="-125" />
</Popup.RenderTransform>
<Border Height="Auto" HorizontalAlignment="Stretch" x:Name="PopupBorder" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" CornerRadius="3">
<Border.Background>
<LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
<GradientStop Color="#FFFFFFFF" Offset="0"/>
<GradientStop Color="#FFFEFEFE" Offset="1"/>
</LinearGradientBrush>
</Border.Background>
<ScrollViewer x:Name="ScrollViewer" BorderThickness="0" Padding="1">
<ItemsPresenter/>
</ScrollViewer>
</Border>
</Popup>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
我必须在这里回答我自己的问题。我关注的是xaml，我没有想到只在组合框控件上添加一个MouseEnter事件处理程序。