感谢 edward.ho.tpe 的回答，我用一个方法给自己写了一个小 EditableComboBoxTextBox里面一个ComboBoxItem。
如果您想多次使用它，最好创建一个 UserControl。
然而我就是这样做的：
样式：
<SolidColorBrush x:Key="TransparentBrush" Color="Transparent"/>
<Style x:Key="ComboBoxItemTextBox" TargetType="TextBox">
<Setter Property="MinWidth" Value="{ThemeResource TextControlThemeMinWidth}"/>
<Setter Property="MinHeight" Value="{ThemeResource TextControlThemeMinHeight}"/>
<Setter Property="Foreground" Value="{ThemeResource TextBoxForegroundThemeBrush}"/>
<Setter Property="Background" Value="{StaticResource TransparentBrush}"/>
<Setter Property="BorderBrush" Value="{StaticResource TransparentBrush}"/>
<Setter Property="SelectionHighlightColor" Value="{ThemeResource TextSelectionHighlightColorThemeBrush}"/>
<Setter Property="BorderThickness" Value="0"/>
<Setter Property="FontFamily" Value="{ThemeResource ContentControlThemeFontFamily}"/>
<Setter Property="FontSize" Value="{ThemeResource ControlContentThemeFontSize}"/>
<Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Hidden"/>
<Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Hidden"/>
<Setter Property="ScrollViewer.IsDeferredScrollingEnabled" Value="False"/>
<Setter Property="Padding" Value="{ThemeResource TextControlThemePadding}"/>
<Setter Property="Margin" Value="-10,0,0,0"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="TextBox">
<Grid>
<Grid.Resources>
<Style x:Name="DeleteButtonStyle" TargetType="Button">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="Button">
<Grid>
<VisualStateManager.VisualStateGroups>
<VisualStateGroup x:Name="CommonStates">
<VisualState x:Name="Normal"/>
<VisualState x:Name="PointerOver">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="BackgroundElement">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextBoxButtonPointerOverBackgroundThemeBrush}"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="BorderElement">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextBoxButtonPointerOverBorderThemeBrush}"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="GlyphElement">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextBoxButtonPointerOverForegroundThemeBrush}"/>
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
<VisualState x:Name="Pressed">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="BackgroundElement">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextBoxButtonPressedBackgroundThemeBrush}"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="BorderElement">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextBoxButtonPressedBorderThemeBrush}"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="GlyphElement">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextBoxButtonPressedForegroundThemeBrush}"/>
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
<VisualState x:Name="Disabled">
<Storyboard>
<DoubleAnimation Duration="0" To="0" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="BackgroundElement"/>
<DoubleAnimation Duration="0" To="0" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="BorderElement"/>
</Storyboard>
</VisualState>
</VisualStateGroup>
</VisualStateManager.VisualStateGroups>
<Border x:Name="BorderElement" BorderBrush="{ThemeResource TextBoxButtonBorderThemeBrush}" BorderThickness="{TemplateBinding BorderThickness}"/>
<Border x:Name="BackgroundElement" Background="{ThemeResource TextBoxButtonBackgroundThemeBrush}" Margin="{TemplateBinding BorderThickness}">
<TextBlock x:Name="GlyphElement" AutomationProperties.AccessibilityView="Raw" Foreground="{ThemeResource TextBoxButtonForegroundThemeBrush}" FontStyle="Normal" FontFamily="{ThemeResource SymbolThemeFontFamily}" HorizontalAlignment="Center" Text="" VerticalAlignment="Center"/>
</Border>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Grid.Resources>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<VisualStateManager.VisualStateGroups>
<VisualStateGroup x:Name="CommonStates">
<VisualState x:Name="Disabled">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="BackgroundElement">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextBoxDisabledBackgroundThemeBrush}"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="BorderElement">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextBoxDisabledBorderThemeBrush}"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="ContentElement">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextBoxDisabledForegroundThemeBrush}"/>
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="PlaceholderTextContentPresenter">
<DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextBoxDisabledForegroundThemeBrush}"/>
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
<VisualState x:Name="Normal">
<Storyboard>
<DoubleAnimation Duration="0" To="{ThemeResource TextControlBackgroundThemeOpacity}" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="BackgroundElement"/>
<DoubleAnimation Duration="0" To="{ThemeResource TextControlBorderThemeOpacity}" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="BorderElement"/>
</Storyboard>
</VisualState>
<VisualState x:Name="PointerOver">
<Storyboard>
<DoubleAnimation Duration="0" To="{ThemeResource TextControlPointerOverBackgroundThemeOpacity}" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="BackgroundElement"/>
<DoubleAnimation Duration="0" To="{ThemeResource TextControlPointerOverBorderThemeOpacity}" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="BorderElement"/>
</Storyboard>
</VisualState>
<VisualState x:Name="Focused"/>
</VisualStateGroup>
<VisualStateGroup x:Name="ButtonStates">
<VisualState x:Name="ButtonVisible"/>
<VisualState x:Name="ButtonCollapsed"/>
</VisualStateGroup>
</VisualStateManager.VisualStateGroups>
<Border x:Name="BackgroundElement" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" Margin="{TemplateBinding BorderThickness}" Grid.Row="1" Grid.RowSpan="1"/>
<Border x:Name="BorderElement" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Grid.ColumnSpan="2" Grid.Row="1" Grid.RowSpan="1"/>
<ContentPresenter x:Name="HeaderContentPresenter" Grid.ColumnSpan="2" ContentTemplate="{TemplateBinding HeaderTemplate}" Content="{TemplateBinding Header}" Foreground="{ThemeResource TextBoxForegroundHeaderThemeBrush}" FontWeight="Semilight" Margin="0,4,0,4" Grid.Row="0"/>
<ScrollViewer x:Name="ContentElement" AutomationProperties.AccessibilityView="Raw" HorizontalScrollMode="{TemplateBinding ScrollViewer.HorizontalScrollMode}" HorizontalScrollBarVisibility="{TemplateBinding ScrollViewer.HorizontalScrollBarVisibility}" IsTabStop="False" IsHorizontalRailEnabled="{TemplateBinding ScrollViewer.IsHorizontalRailEnabled}" IsVerticalRailEnabled="{TemplateBinding ScrollViewer.IsVerticalRailEnabled}" IsDeferredScrollingEnabled="{TemplateBinding ScrollViewer.IsDeferredScrollingEnabled}" Margin="{TemplateBinding BorderThickness}" Padding="{TemplateBinding Padding}" Grid.Row="1" VerticalScrollBarVisibility="{TemplateBinding ScrollViewer.VerticalScrollBarVisibility}" VerticalScrollMode="{TemplateBinding ScrollViewer.VerticalScrollMode}" ZoomMode="Disabled"/>
<ContentControl x:Name="PlaceholderTextContentPresenter" Grid.ColumnSpan="2" Content="{TemplateBinding PlaceholderText}" Foreground="{ThemeResource TextBoxPlaceholderTextThemeBrush}" IsHitTestVisible="False" IsTabStop="False" Margin="{TemplateBinding BorderThickness}" Padding="{TemplateBinding Padding}" Grid.Row="1"/>
<Button x:Name="DeleteButton" BorderThickness="{TemplateBinding BorderThickness}" Grid.Column="1" FontSize="{TemplateBinding FontSize}" IsTabStop="False" Grid.Row="1" Style="{StaticResource DeleteButtonStyle}" Visibility="Collapsed" VerticalAlignment="Stretch"/>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
组合框：
<ComboBox SelectionChanged="ComboBox_SelectionChanged">
<ComboBoxItem IsSelected="True">
<TextBox x:Name="tbComboBox" Style="{StaticResource ComboBoxItemTextBox}" KeyDown="tbComboBox_KeyDown"/>
</ComboBoxItem>
<ComboBoxItem>Item 1</ComboBoxItem>
<ComboBoxItem>Item 2</ComboBoxItem>
<ComboBoxItem>Item 3</ComboBoxItem>
<ComboBoxItem>Item 4</ComboBoxItem>
</ComboBox>
事件处理程序：
private void ComboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
if (e.AddedItems.Count == 1 && e.AddedItems[0] != (sender as ComboBox).Items[0])
{
(sender as ComboBox).SelectedIndex = 0;
tbComboBox.Text = (e.AddedItems[0] as ComboBoxItem).Content as String;
}
}
private void tbComboBox_KeyDown(object sender, KeyRoutedEventArgs e)
{
if (e.Key == Windows.System.VirtualKey.Space)
{
if (tbComboBox.SelectionLength > 0)
{
tbComboBox.Text = tbComboBox.Text.Remove(tbComboBox.SelectionStart, tbComboBox.SelectionLength);
tbComboBox.SelectionLength = 0;
}
int pos = tbComboBox.SelectionStart;
tbComboBox.Text = tbComboBox.Text.Insert(pos, " ");
tbComboBox.SelectionStart = pos + 1;
e.Handled = true;
}
}
基本上这是什么：
正如 edward.ho.tpe 建议的那样TextBox作为 a 的第一项的内容ComboBox.
The TextBox有一个自定义样式，可以删除背景、边框，将其向左移动一点（可选 - 但我喜欢它，因为它提供了更多的书写空间），并将删除按钮更改为保持折叠状态。
这SelectionChanged事件处理程序确保TextBox保持SelectedItem并且只改变Text根据所选项目的内容和KeyDown事件处理程序处理空格键，否则会触发下拉菜单ComboBox.
