silverlight - 如何在 silverlight 文本框上设置垂直内容对齐

Question

我有一个 silverlight 文本框，它将所有文本对齐到中心。 VerticalContentAlignment 不起作用! 如何对齐此文本，使文本从顶部开始而不是从中心开始。

<StackPanel>
    <TextBox Text="{Binding OverView,Mode=TwoWay}" AcceptsReturn="True" 
    Loaded="Update_EditableState" 
    Height="135" HorizontalAlignment="Left" 
    TextWrapping="Wrap" Width="200">
    </TextBox>
</StackPanel>

Answer 1

根据 Microsoft documentation VerticalContentAlignment 不适用于文本框的默认模板。

为了解决这个问题，我们需要自己的风格。 将绑定(bind) VerticalAlignment 添加到模板的 VerticalContentAlignment 解决了该问题。

这是我从标准文本框样式更改的元素

<ScrollViewer x:Name="ContentElement" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" Padding="{TemplateBinding Padding}" BorderThickness="0" IsTabStop="False"/>

这是我用来实现此目的的完整样式

<Style x:Key="TextBoxWithVerticalContentAlignment" TargetType="TextBox">
        <Setter Property="BorderThickness" Value="1"/>
        <Setter Property="Background" Value="#FFFFFFFF"/>
        <Setter Property="Foreground" Value="#FF000000"/>
        <Setter Property="Padding" Value="2"/>
        <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="TextBox">
                    <Grid x:Name="RootElement">
                        <vsm:VisualStateManager.VisualStateGroups>
                            <vsm:VisualStateGroup x:Name="CommonStates">
                                <vsm:VisualState x:Name="Normal"/>
                                <vsm:VisualState x:Name="MouseOver">
                                    <Storyboard>
                                        <ColorAnimation Storyboard.TargetName="MouseOverBorder" Storyboard.TargetProperty="(Border.BorderBrush).(SolidColorBrush.Color)" To="#FF99C1E2" Duration="0"/>
                                    </Storyboard>
                                </vsm:VisualState>
                                <vsm:VisualState x:Name="Disabled">
                                    <Storyboard>
                                        <DoubleAnimation Storyboard.TargetName="DisabledVisualElement" Storyboard.TargetProperty="Opacity" To="1" Duration="0"/>
                                    </Storyboard>
                                </vsm:VisualState>
                                <vsm:VisualState x:Name="ReadOnly">
                                    <Storyboard>
                                        <DoubleAnimation Storyboard.TargetName="ReadOnlyVisualElement" Storyboard.TargetProperty="Opacity" To="1" Duration="0" />
                                    </Storyboard>
                                </vsm:VisualState>
                            </vsm:VisualStateGroup>
                            <vsm:VisualStateGroup x:Name="FocusStates">
                                <vsm:VisualState x:Name="Focused">
                                    <Storyboard>
                                        <DoubleAnimation Storyboard.TargetName="FocusVisualElement" Storyboard.TargetProperty="Opacity" To="1" Duration="0"/>
                                    </Storyboard>
                                </vsm:VisualState>
                                <vsm:VisualState x:Name="Unfocused">
                                    <Storyboard>
                                        <DoubleAnimation Storyboard.TargetName="FocusVisualElement" Storyboard.TargetProperty="Opacity" To="0" Duration="0"/>
                                    </Storyboard>
                                </vsm:VisualState>
                            </vsm:VisualStateGroup>
                            <vsm:VisualStateGroup x:Name="ValidationStates">
                                <vsm:VisualState x:Name="Valid"/>
                                <vsm:VisualState x:Name="InvalidUnfocused">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="ValidationErrorElement" Storyboard.TargetProperty="Visibility">
                                            <DiscreteObjectKeyFrame KeyTime="0">
                                                <DiscreteObjectKeyFrame.Value>
                                                    <Visibility>Visible</Visibility>
                                                </DiscreteObjectKeyFrame.Value>
                                            </DiscreteObjectKeyFrame>
                                        </ObjectAnimationUsingKeyFrames>
                                    </Storyboard>
                                </vsm:VisualState>
                                <vsm:VisualState x:Name="InvalidFocused">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="ValidationErrorElement" Storyboard.TargetProperty="Visibility">
                                            <DiscreteObjectKeyFrame KeyTime="0">
                                                <DiscreteObjectKeyFrame.Value>
                                                    <Visibility>Visible</Visibility>
                                                </DiscreteObjectKeyFrame.Value>
                                            </DiscreteObjectKeyFrame>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="validationTooltip" Storyboard.TargetProperty="IsOpen">
                                            <DiscreteObjectKeyFrame KeyTime="0">
                                                <DiscreteObjectKeyFrame.Value>
                                                    <sys:Boolean>True</sys:Boolean>
                                                </DiscreteObjectKeyFrame.Value>
                                            </DiscreteObjectKeyFrame>
                                        </ObjectAnimationUsingKeyFrames>
                                    </Storyboard>
                                </vsm:VisualState>
                            </vsm:VisualStateGroup>
                        </vsm:VisualStateManager.VisualStateGroups>
                        <Border x:Name="Border" BorderThickness="{TemplateBinding BorderThickness}" CornerRadius="1" Opacity="1" Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}">
                            <Grid>
                                <Border x:Name="ReadOnlyVisualElement" Opacity="0" Background="#5EC9C9C9"/>
                                <Border x:Name="MouseOverBorder" Background="White" BorderThickness="1" BorderBrush="Transparent">
                                    <ScrollViewer x:Name="ContentElement" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" Padding="{TemplateBinding Padding}" BorderThickness="0" IsTabStop="False"/>
                                </Border>
                            </Grid>
                        </Border>
                        <Border x:Name="DisabledVisualElement" Background="#A5F7F7F7" BorderBrush="#A5F7F7F7" BorderThickness="{TemplateBinding BorderThickness}" Opacity="0" IsHitTestVisible="False"/>
                        <Border x:Name="FocusVisualElement" BorderBrush="#FF6DBDD1" BorderThickness="{TemplateBinding BorderThickness}" Margin="1" Opacity="0" IsHitTestVisible="False"/>
                        <Border x:Name="ValidationErrorElement" BorderThickness="1" CornerRadius="1" BorderBrush="#FFDB000C" Visibility="Collapsed">
                            <ToolTipService.ToolTip>
                                <ToolTip x:Name="validationTooltip" Template="{StaticResource ValidationToolTipTemplate}" Placement="Right" 
                         PlacementTarget="{Binding RelativeSource={RelativeSource TemplatedParent}}"
                         DataContext="{Binding RelativeSource={RelativeSource TemplatedParent}}">
                                    <ToolTip.Triggers>
                                        <EventTrigger RoutedEvent="Canvas.Loaded">
                                            <EventTrigger.Actions>
                                                <BeginStoryboard>
                                                    <Storyboard>
                                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="validationTooltip" Storyboard.TargetProperty="IsHitTestVisible">
                                                            <DiscreteObjectKeyFrame KeyTime="0">
                                                                <DiscreteObjectKeyFrame.Value>
                                                                    <sys:Boolean>true</sys:Boolean>
                                                                </DiscreteObjectKeyFrame.Value>
                                                            </DiscreteObjectKeyFrame>
                                                        </ObjectAnimationUsingKeyFrames>
                                                    </Storyboard>
                                                </BeginStoryboard>
                                            </EventTrigger.Actions>
                                        </EventTrigger>
                                    </ToolTip.Triggers>
                                </ToolTip>
                            </ToolTipService.ToolTip>
                            <Grid Width="12" Height="12" HorizontalAlignment="Right" Margin="1,-4,-4,0" VerticalAlignment="Top" Background="Transparent">
                                <Path Margin="1,3,0,0" Data="M 1,0 L6,0 A 2,2 90 0 1 8,2 L8,7 z" Fill="#FFDC000C"/>
                                <Path Margin="1,3,0,0" Data="M 0,0 L2,0 L 8,6 L8,8" Fill="#ffffff"/>
                            </Grid>
                        </Border>
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

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