当组合框打开时,Silverlight Combobox 触发 KeyDown 事件

Silverlight Combobox Fire KeyDown event when combobox is open

我有一个 Silverlight Combobox(恰好在 StackPanel 中),在 KeyDown 事件上有一个事件处理程序。该处理程序仅在 ComboBox 关闭时才起作用,因此需要点击 2 次才能触发它。

有没有办法在 ComboBox 打开时触发 KeyDown 事件或执行等效操作?

您必须在 ComboBox 的模板中为 ItemsPresenter 处理 KeyUp/KeyDown。在我的测试中,与 KeyDown.

相比,KeyUp 提供了更平滑的过渡


编辑:如果你必须将你的风格保存在一个单独的字典中,那么你可以这样做:

XAML:

<UserControl
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:local="clr-namespace:SilverlightApplication5"
    x:Class="SilverlightApplication5.MainPage"
    mc:Ignorable="d"
    d:DesignHeight="300" d:DesignWidth="400">

    <UserControl.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <ResourceDictionary Source="Dictionary1.xaml"/>
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </UserControl.Resources>

    <Grid x:Name="LayoutRoot" Background="White">
        <StackPanel Orientation="Horizontal"
                    VerticalAlignment="Center"
                    HorizontalAlignment="Center">
            <local:MyComboBox x:Name="cbx1" 
                      FontSize="24"
                      SelectedIndex="0"
                      Margin="0,0,10,0"
                      Style="{StaticResource ComboBoxStyle1}">
                <ComboBoxItem Content="Option 1"/>
                <ComboBoxItem Content="Option 2"/>
                <ComboBoxItem Content="Option 3"/>
            </local:MyComboBox>
            <TextBlock x:Name="txt1" 
                   VerticalAlignment="Center"
                   HorizontalAlignment="Center"
                   FontSize="24"
                   Text="{Binding ElementName=cbx1, Path=SelectedItem.Content}"/>
        </StackPanel>
    </Grid>
</UserControl>

我的组合框:

public class MyComboBox : ComboBox
{
    public MyComboBox()
    {
        this.DefaultStyleKey = typeof(MyComboBox);
    }

    public override void OnApplyTemplate()
    {
        base.OnApplyTemplate();

        var itemsPresenter = GetTemplateChild("Ip1") as UIElement;

        if (itemsPresenter != null)
            itemsPresenter.KeyUp += ItemsPresenter_KeyUp;

    }

    private void ItemsPresenter_KeyUp(object sender, KeyEventArgs e)
    {
        SelectedItem = e.OriginalSource;
    }
}

词典:

<ResourceDictionary
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:local="clr-namespace:SilverlightApplication5"
    xmlns:System="clr-namespace:System;assembly=mscorlib">

    <ControlTemplate x:Key="ValidationToolTipTemplate">
        <!-- Content removed due to a 30,000 character-limit per post. -->
    </ControlTemplate>

    <Style x:Key="ComboBoxStyle1" TargetType="local:MyComboBox">
        <Setter Property="Padding" Value="6,2,25,2"/>
        <Setter Property="Background" Value="#FF1F3B53"/>
        <Setter Property="HorizontalContentAlignment" Value="Left"/>
        <Setter Property="BorderThickness" Value="1"/>
        <Setter Property="TabNavigation" Value="Once"/>
        <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Auto"/>
        <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto"/>
        <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="ComboBox">
                    <Grid>
                        <Grid.Resources>
                            <Style x:Name="comboToggleStyle" TargetType="ToggleButton">
                                <Setter Property="Foreground" Value="#FF333333"/>
                                <Setter Property="Background" Value="#FF1F3B53"/>
                                <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="BorderThickness" Value="1"/>
                                <Setter Property="Padding" Value="3"/>
                                <Setter Property="Template">
                                    <Setter.Value>
                                        <ControlTemplate TargetType="ToggleButton">
                                            <Grid>
                                                <VisualStateManager.VisualStateGroups>
                                                    <VisualStateGroup x:Name="CommonStates">
                                                        <VisualState x:Name="Normal"/>
                                                        <VisualState x:Name="MouseOver">
                                                            <Storyboard>
                                                                <DoubleAnimation Duration="0" To="1" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="BackgroundOverlay"/>
                                                                <ColorAnimation Duration="0" To="#7FFFFFFF" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[3].(GradientStop.Color)" Storyboard.TargetName="BackgroundGradient"/>
                                                                <ColorAnimation Duration="0" To="#CCFFFFFF" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[2].(GradientStop.Color)" Storyboard.TargetName="BackgroundGradient"/>
                                                                <ColorAnimation Duration="0" To="#F2FFFFFF" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[1].(GradientStop.Color)" Storyboard.TargetName="BackgroundGradient"/>
                                                            </Storyboard>
                                                        </VisualState>
                                                        <VisualState x:Name="Pressed">
                                                            <Storyboard>
                                                                <DoubleAnimation Duration="0" To="1" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="BackgroundOverlay2"/>
                                                                <DoubleAnimation Duration="0" To="1" Storyboard.TargetProperty="(UIElement.Opacity)" Storyboard.TargetName="Highlight"/>
                                                                <ColorAnimation Duration="0" To="#E5FFFFFF" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[1].(GradientStop.Color)" Storyboard.TargetName="BackgroundGradient"/>
                                                                <ColorAnimation Duration="0" To="#BCFFFFFF" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[2].(GradientStop.Color)" Storyboard.TargetName="BackgroundGradient"/>
                                                                <ColorAnimation Duration="0" To="#6BFFFFFF" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[3].(GradientStop.Color)" Storyboard.TargetName="BackgroundGradient"/>
                                                                <ColorAnimation Duration="0" To="#F2FFFFFF" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[0].(GradientStop.Color)" Storyboard.TargetName="BackgroundGradient"/>
                                                            </Storyboard>
                                                        </VisualState>
                                                        <VisualState x:Name="Disabled"/>
                                                    </VisualStateGroup>
                                                    <VisualStateGroup x:Name="CheckStates">
                                                        <VisualState x:Name="Checked">
                                                            <Storyboard>
                                                                <DoubleAnimation Duration="0" To="1" Storyboard.TargetProperty="(UIElement.Opacity)" Storyboard.TargetName="BackgroundOverlay3"/>
                                                                <DoubleAnimation Duration="0" To="1" Storyboard.TargetProperty="(UIElement.Opacity)" Storyboard.TargetName="Highlight"/>
                                                                <DoubleAnimation Duration="0" To="1" Storyboard.TargetProperty="(UIElement.Opacity)" Storyboard.TargetName="BackgroundGradient2"/>
                                                                <ColorAnimation Duration="0" To="#E5FFFFFF" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[1].(GradientStop.Color)" Storyboard.TargetName="BackgroundGradient2"/>
                                                                <ColorAnimation Duration="0" To="#BCFFFFFF" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[2].(GradientStop.Color)" Storyboard.TargetName="BackgroundGradient2"/>
                                                                <ColorAnimation Duration="0" To="#6BFFFFFF" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[3].(GradientStop.Color)" Storyboard.TargetName="BackgroundGradient2"/>
                                                                <ColorAnimation Duration="0" To="#F2FFFFFF" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[0].(GradientStop.Color)" Storyboard.TargetName="BackgroundGradient2"/>
                                                            </Storyboard>
                                                        </VisualState>
                                                        <VisualState x:Name="Unchecked"/>
                                                    </VisualStateGroup>
                                                    <VisualStateGroup x:Name="FocusStates">
                                                        <VisualState x:Name="Focused">
                                                            <Storyboard>
                                                                <ObjectAnimationUsingKeyFrames Duration="0" Storyboard.TargetProperty="Visibility" Storyboard.TargetName="FocusVisualElement">
                                                                    <DiscreteObjectKeyFrame KeyTime="0">
                                                                        <DiscreteObjectKeyFrame.Value>
                                                                            <Visibility>Visible</Visibility>
                                                                        </DiscreteObjectKeyFrame.Value>
                                                                    </DiscreteObjectKeyFrame>
                                                                </ObjectAnimationUsingKeyFrames>
                                                            </Storyboard>
                                                        </VisualState>
                                                        <VisualState x:Name="Unfocused"/>
                                                    </VisualStateGroup>
                                                </VisualStateManager.VisualStateGroups>
                                                <Rectangle x:Name="Background" Fill="{TemplateBinding Background}" RadiusY="3" RadiusX="3" Stroke="{TemplateBinding BorderBrush}" StrokeThickness="{TemplateBinding BorderThickness}"/>
                                                <Rectangle x:Name="BackgroundOverlay" Fill="#FF448DCA" Opacity="0" RadiusY="3" RadiusX="3" Stroke="#00000000" StrokeThickness="{TemplateBinding BorderThickness}"/>
                                                <Rectangle x:Name="BackgroundOverlay2" Fill="#FF448DCA" Opacity="0" RadiusY="3" RadiusX="3" Stroke="#00000000" StrokeThickness="{TemplateBinding BorderThickness}"/>
                                                <Rectangle x:Name="BackgroundGradient" Margin="{TemplateBinding BorderThickness}" RadiusY="2" RadiusX="2" Stroke="#FFFFFFFF" StrokeThickness="1">
                                                    <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" Fill="#FF448DCA" Opacity="0" RadiusY="3" RadiusX="3" Stroke="#00000000" StrokeThickness="{TemplateBinding BorderThickness}"/>
                                                <Rectangle x:Name="BackgroundGradient2" Margin="{TemplateBinding BorderThickness}" Opacity="0" RadiusY="2" RadiusX="2" Stroke="#FFFFFFFF" StrokeThickness="1">
                                                    <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="Highlight" IsHitTestVisible="false" Margin="{TemplateBinding BorderThickness}" Opacity="0" RadiusY="2" RadiusX="2" Stroke="#FF6DBDD1" StrokeThickness="1"/>
                                                <ContentPresenter x:Name="contentPresenter" ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
                                                <Rectangle x:Name="FocusVisualElement" IsHitTestVisible="false" Margin="1" RadiusY="3.5" RadiusX="3.5" Stroke="#FF6DBDD1" StrokeThickness="1" Visibility="Collapsed"/>
                                            </Grid>
                                        </ControlTemplate>
                                    </Setter.Value>
                                </Setter>
                            </Style>
                        </Grid.Resources>
                        <VisualStateManager.VisualStateGroups>
                            <VisualStateGroup x:Name="CommonStates">
                                <VisualState x:Name="Normal"/>
                                <VisualState x:Name="MouseOver"/>
                                <VisualState x:Name="Disabled">
                                    <Storyboard>
                                        <DoubleAnimation Duration="00:00:00" To=".55" Storyboard.TargetProperty="(UIElement.Opacity)" Storyboard.TargetName="DisabledVisualElement"/>
                                    </Storyboard>
                                </VisualState>
                            </VisualStateGroup>
                            <VisualStateGroup x:Name="FocusStates">
                                <VisualState x:Name="Focused">
                                    <Storyboard>
                                        <DoubleAnimation Duration="00:00:00" To="1" Storyboard.TargetProperty="(UIElement.Opacity)" Storyboard.TargetName="FocusVisualElement"/>
                                    </Storyboard>
                                </VisualState>
                                <VisualState x:Name="Unfocused"/>
                                <VisualState x:Name="FocusedDropDown">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Duration="00:00:00" Storyboard.TargetProperty="(UIElement.Visibility)" Storyboard.TargetName="PopupBorder">
                                            <DiscreteObjectKeyFrame KeyTime="00:00:00">
                                                <DiscreteObjectKeyFrame.Value>
                                                    <Visibility>Visible</Visibility>
                                                </DiscreteObjectKeyFrame.Value>
                                            </DiscreteObjectKeyFrame>
                                        </ObjectAnimationUsingKeyFrames>
                                    </Storyboard>
                                </VisualState>
                            </VisualStateGroup>
                            <VisualStateGroup x:Name="ValidationStates">
                                <VisualState x:Name="Valid"/>
                                <VisualState x:Name="InvalidUnfocused">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility" Storyboard.TargetName="ValidationErrorElement">
                                            <DiscreteObjectKeyFrame KeyTime="0">
                                                <DiscreteObjectKeyFrame.Value>
                                                    <Visibility>Visible</Visibility>
                                                </DiscreteObjectKeyFrame.Value>
                                            </DiscreteObjectKeyFrame>
                                        </ObjectAnimationUsingKeyFrames>
                                    </Storyboard>
                                </VisualState>
                                <VisualState x:Name="InvalidFocused">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility" Storyboard.TargetName="ValidationErrorElement">
                                            <DiscreteObjectKeyFrame KeyTime="0">
                                                <DiscreteObjectKeyFrame.Value>
                                                    <Visibility>Visible</Visibility>
                                                </DiscreteObjectKeyFrame.Value>
                                            </DiscreteObjectKeyFrame>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="IsOpen" Storyboard.TargetName="validationTooltip">
                                            <DiscreteObjectKeyFrame KeyTime="0">
                                                <DiscreteObjectKeyFrame.Value>
                                                    <System:Boolean>True</System:Boolean>
                                                </DiscreteObjectKeyFrame.Value>
                                            </DiscreteObjectKeyFrame>
                                        </ObjectAnimationUsingKeyFrames>
                                    </Storyboard>
                                </VisualState>
                            </VisualStateGroup>
                        </VisualStateManager.VisualStateGroups>
                        <Border x:Name="ContentPresenterBorder">
                            <Grid>
                                <ToggleButton x:Name="DropDownToggle" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" HorizontalAlignment="Stretch" HorizontalContentAlignment="Right" Margin="0" Style="{StaticResource comboToggleStyle}" VerticalAlignment="Stretch">
                                    <Path x:Name="BtnArrow" Data="F1 M 301.14,-189.041L 311.57,-189.041L 306.355,-182.942L 301.14,-189.041 Z " HorizontalAlignment="Right" Height="4" Margin="0,0,6,0" Stretch="Uniform" Width="8">
                                        <Path.Fill>
                                            <SolidColorBrush x:Name="BtnArrowColor" Color="#FF333333"/>
                                        </Path.Fill>
                                    </Path>
                                </ToggleButton>
                                <ContentPresenter x:Name="ContentPresenter" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}">
                                    <TextBlock Text=" "/>
                                </ContentPresenter>
                            </Grid>
                        </Border>
                        <Rectangle x:Name="DisabledVisualElement" Fill="White" IsHitTestVisible="false" Opacity="0" RadiusY="3" RadiusX="3"/>
                        <Rectangle x:Name="FocusVisualElement" IsHitTestVisible="false" Margin="1" Opacity="0" RadiusY="2" RadiusX="2" Stroke="#FF6DBDD1" StrokeThickness="1"/>
                        <Border x:Name="ValidationErrorElement" BorderBrush="#FFDB000C" BorderThickness="1" CornerRadius="1" Visibility="Collapsed">
                            <ToolTipService.ToolTip>
                                <ToolTip x:Name="validationTooltip" DataContext="{Binding RelativeSource={RelativeSource TemplatedParent}}" Placement="Right" PlacementTarget="{Binding RelativeSource={RelativeSource TemplatedParent}}" Template="{StaticResource ValidationToolTipTemplate}">
                                    <ToolTip.Triggers>
                                        <EventTrigger RoutedEvent="Canvas.Loaded">
                                            <BeginStoryboard>
                                                <Storyboard>
                                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="IsHitTestVisible" Storyboard.TargetName="validationTooltip">
                                                        <DiscreteObjectKeyFrame KeyTime="0">
                                                            <DiscreteObjectKeyFrame.Value>
                                                                <System:Boolean>true</System:Boolean>
                                                            </DiscreteObjectKeyFrame.Value>
                                                        </DiscreteObjectKeyFrame>
                                                    </ObjectAnimationUsingKeyFrames>
                                                </Storyboard>
                                            </BeginStoryboard>
                                        </EventTrigger>
                                    </ToolTip.Triggers>
                                </ToolTip>
                            </ToolTipService.ToolTip>
                            <Grid Background="Transparent" HorizontalAlignment="Right" Height="12" Margin="1,-4,-4,0" VerticalAlignment="Top" Width="12">
                                <Path Data="M 1,0 L6,0 A 2,2 90 0 1 8,2 L8,7 z" Fill="#FFDC000C" Margin="1,3,0,0"/>
                                <Path Data="M 0,0 L2,0 L 8,6 L8,8" Fill="#ffffff" Margin="1,3,0,0"/>
                            </Grid>
                        </Border>
                        <Popup x:Name="Popup">
                            <Border x:Name="PopupBorder" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" CornerRadius="3" HorizontalAlignment="Stretch" Height="Auto">
                                <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 x:Name="Ip1" />
                                </ScrollViewer>
                            </Border>
                        </Popup>
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

</ResourceDictionary>