有没有办法在UWP中自定义默认的TextBox控件？我需要把“X”按钮变小

在UWP（Universal Windows Platform）中，TextBox 控件默认提供了一个清除按钮（通常显示为“X”），允许用户快速清除文本框中的内容。如果你想要自定义这个清除按钮的大小，可以通过修改控件的样式来实现。

基础概念

UWP中的TextBox控件支持通过样式（Style）和模板（Template）来自定义其外观和行为。你可以使用XAML来定义一个新的样式，并在其中修改清除按钮的大小。

类型与应用场景

类型：自定义样式适用于需要对标准控件进行视觉调整的场景。
应用场景：当默认控件的外观不符合应用的视觉设计标准时，或者需要提供特定的用户体验时。

示例代码

以下是一个简单的示例，展示了如何在UWP中自定义TextBox控件的清除按钮大小：

<Page.Resources>
    <Style x:Key="CustomTextBoxStyle" TargetType="TextBox">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="TextBox">
                    <Grid>
                        <VisualStateManager.VisualStateGroups>
                            <VisualStateGroup x:Name="CommonStates">
                                <VisualState x:Name="Disabled">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="HeaderContentPresenter" Storyboard.TargetProperty="Foreground">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource SystemControlDisabledBaseMediumLowBrush}" />
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="BackgroundElement" Storyboard.TargetProperty="Background">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource SystemControlDisabledTransparentBrush}" />
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="BorderElement" Storyboard.TargetProperty="Background">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource SystemControlBackgroundBaseLowBrush}" />
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="BorderElement" Storyboard.TargetProperty="BorderBrush">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource SystemControlDisabledBaseLowBrush}" />
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="ContentElement" Storyboard.TargetProperty="Foreground">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource SystemControlDisabledChromeDisabledLowBrush}" />
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetName="PlaceholderTextContentPresenter" Storyboard.TargetProperty="Foreground">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource SystemControlDisabledChromeDisabledLowBrush}" />
                                        </ObjectAnimationUsingKeyFrames>
                                    </Storyboard>
                                </VisualState>
                            </VisualStateGroup>
                        </VisualStateManager.VisualStateGroups>
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition Width="*" />
                            <ColumnDefinition Width="Auto" />
                        </Grid.ColumnDefinitions>
                        <Border x:Name="BackgroundElement" Grid.ColumnSpan="2" Background="{TemplateBinding Background}" Margin="{TemplateBinding Padding}" />
                        <ContentPresenter x:Name="HeaderContentPresenter" Grid.ColumnSpan="2" ContentTemplate="{TemplateBinding HeaderTemplate}" Content="{TemplateBinding Header}" Foreground="{ThemeResource SystemControlForegroundBaseHighBrush}" FontWeight="Semilight" Margin="0,0,0,-4" Visibility="Collapsed" x:DeferLoadStrategy="Lazy" />
                        <ScrollViewer x:Name="ContentElement" Grid.Column="0" HorizontalScrollMode="{TemplateBinding HorizontalScrollMode}" HorizontalScrollBarVisibility="{TemplateBinding HorizontalScrollBarVisibility}" IsTabStop="False" IsHorizontalRailEnabled="True" IsVerticalRailEnabled="True" Margin="{TemplateBinding BorderThickness}" Padding="{TemplateBinding Padding}" VerticalScrollBarVisibility="{TemplateBinding VerticalScrollBarVisibility}" VerticalScrollMode="{TemplateBinding VerticalScrollMode}" ZoomMode="Disabled" />
                        <ContentControl x:Name="PlaceholderTextContentPresenter" Grid.Column="0" Content="{TemplateBinding PlaceholderText}" Foreground="{ThemeResource SystemControlPageTextBaseMediumBrush}" HorizontalAlignment="Left" Margin="{TemplateBinding Padding}" Grid.ColumnSpan="2" IsTabStop="False" VerticalAlignment="Center" Visibility="Collapsed" />
                        <Button x:Name="ClearButton" Grid.Column="1" Content="X" FontSize="10" Width="20" Height="20" Margin="0,-4,4,0" Visibility="Collapsed" />
                        <Border x:Name="BorderElement" Grid.ColumnSpan="2" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" />
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</Page.Resources>

<TextBox Style="{StaticResource CustomTextBoxStyle}" />