带下拉菜单的自动完成框
AutoCompleteBox非常棒，但它缺少的一个功能是点按即可下拉所有可用选项。您可以通过设置MinimumPrefixLength = 0来结束 - 这样，用户可以通过删除文本来获取完整的下拉列表。但是这有一些限制：
- 如果没有文字开头，则用户必须输入一些文字并将其删除（非直观且不方便）
- click-and-keypress序列似乎是次优的UX。
如果用户点击控件（或者，右边的按钮），你会如何调整此控件以使其下拉完整的选项列表？
看来我对@HighCore很失望。到目前为止，我尝试在控件模板上添加一个按钮，触发打开Popup。这种方法的缺点是，如果输入了文本，则按照正常的过滤规则过滤列表。现在，您可以清除文本，从而删除过滤器，但这会产生另一个副作用：取消选择当前选定的项目（与ComboBox相反，ComboBox的下拉菜单可以打开而不需要de - 选择）。所以现在怎么办？暂时删除过滤器，并在弹出窗口关闭或用户键入其他内容时将其恢复？
2 个答案:
答案 0 :(得分：2)
我构建了一个这样的控件，我使用的方法是从AutoComboBox控件继承并在下拉列表打开时删除过滤器。
<强> 修改 代码已更新，包含缺少的资源。
代码是：
public class AutoCompleteComboBox : AutoCompleteBox
{
/// <summary>
/// Occurs when drop down toggle button is clicked.
/// </summary>
public event EventHandler ToggleButtonClick;
private object _holdSelectedItem;
private AutoCompleteFilterMode _holdFilterMode;
/// <summary>
/// Identifies the DisplayMemberPath dependency property.
/// </summary>
public static readonly DependencyProperty DisplayMemberPathProperty = DependencyProperty.Register("DisplayMemberPath", typeof(string), typeof(AutoCompleteComboBox), new PropertyMetadata(string.Empty, DisplayMemberPath_PropertyChanged));
/// <summary>
/// Gets or sets the name or path of the property
/// that is displayed for each the data item in the control.
/// </summary>
public string DisplayMemberPath
{
get { return (string)GetValue(DisplayMemberPathProperty); }
set { SetValue(DisplayMemberPathProperty, value); }
}
private static void DisplayMemberPath_PropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var accb = (AutoCompleteComboBox)d;
accb.ValueMemberPath = e.NewValue.ToString();
}
/// <summary>
/// Identifies the MaxLength dependency property.
/// </summary>
public static readonly DependencyProperty MaxLengthProperty = DependencyProperty.Register("MaxLength", typeof(int), typeof(AutoCompleteComboBox), null);
/// <summary>
/// Gets or sets the maximum number of characters allowed for user input.
/// </summary>
public int MaxLength
{
get { return (int)GetValue(MaxLengthProperty); }
set { SetValue(MaxLengthProperty, value); }
}
/// <summary>
/// Gets or sets a collection used to generate the content of the control.
/// </summary>
public new IEnumerable ItemsSource
{
get { return GetValue(ItemsSourceProperty) as IEnumerable; }
set
{
SetValue(SelectedItemProperty, null);
SetValue(ItemsSourceProperty, value);
Dispatcher.BeginInvoke(() => SetValue(TextProperty, string.Empty));
_holdSelectedItem = null;
}
}
/// <summary>
/// Initializes a new instance of the AutoCompleteComboBox control.
/// </summary>
public AutoCompleteComboBox()
{
StreamResourceInfo sri = Application.GetResourceStream(new Uri("/UI.Controls;component/AutoCompleteComboBox.xaml", UriKind.Relative));
var sr = new StreamReader(sri.Stream);
Style = (Style)XamlReader.Load(sr.ReadToEnd());
DropDownClosed += AutoCompleteComboBox_DropDownClosed;
DropDownOpened += AutoCompleteComboBox_DropDownOpened;
}
/// <summary>
/// Called when the template's tree is generated.
/// </summary>
public override void OnApplyTemplate()
{
base.OnApplyTemplate();
var toggle = (ToggleButton)GetTemplateChild("PopupToggleButton");
toggle.Click += DropDownToggle_Click;
var lb = (ListBox)GetTemplateChild("Selector");
lb.DisplayMemberPath = DisplayMemberPath;
_holdFilterMode = FilterMode;
TextChanged += AutoCompleteComboBox_TextChanged;
SelectionChanged += new SelectionChangedEventHandler(AutoCompleteComboBox_SelectionChanged);
}
private void AutoCompleteComboBox_DropDownClosed(object sender, RoutedPropertyChangedEventArgs<bool> e)
{
if (SelectedItem == null && _holdSelectedItem != null && SelectedItem != _holdSelectedItem && ItemsSource.Cast<object>().Contains(_holdSelectedItem))
{
SelectedItem = _holdSelectedItem;
}
_holdSelectedItem = null;
FilterMode = _holdFilterMode;
}
private void AutoCompleteComboBox_DropDownOpened(object sender, RoutedPropertyChangedEventArgs<bool> e)
{
var lb = (ListBox)GetTemplateChild("Selector");
ScrollViewer sv = lb.GetScrollHost();
if (sv != null)
{
sv.ScrollToTop();
}
if (SelectedItem != null)
{
lb.SelectedItem = SelectedItem;
_holdSelectedItem = SelectedItem;
}
}
private void DropDownToggle_Click(object sender, RoutedEventArgs e)
{
IsDropDownOpen = !IsDropDownOpen;
if (ToggleButtonClick != null)
{
ToggleButtonClick(this, e);
}
if (IsDropDownOpen)
{
_holdFilterMode = FilterMode;
FilterMode = AutoCompleteFilterMode.None;
((TextBox)GetTemplateChild("Text")).SelectAll();
}
Focus();
}
private void AutoCompleteComboBox_TextChanged(object sender, RoutedEventArgs e)
{
if (IsDropDownOpen)
{
if (FilterMode == AutoCompleteFilterMode.None && FilterMode != _holdFilterMode)
{
FilterMode = _holdFilterMode;
}
ScrollViewer sv = ((ListBox)GetTemplateChild("Selector")).GetScrollHost();
if (sv != null)
{
sv.ScrollToTop();
}
}
}
private void AutoCompleteComboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
if (!IsDropDownOpen && SelectedItem == null)
{
Text = string.Empty;
}
}
}
<Setter Property="Height" Value="24" />
<Setter Property="MinimumPopulateDelay" Value="1" />
<Setter Property="IsTextCompletionEnabled" Value="False" />
<Setter Property="MinimumPrefixLength" Value="0" />
<Setter Property="MaxDropDownHeight" Value="300" />
<Setter Property="IsTabStop" Value="False" />
<Setter Property="Padding" Value="2" />
<Setter Property="BorderThickness" Value="1" />
<Setter Property="BorderBrush" Value="#FF000000" />
<Setter Property="Background" Value="#FFFFFFFF" />
<Setter Property="Foreground" Value="#FF000000" />
<Setter Property="MinWidth" Value="45" />
<Setter Property="FilterMode" Value="Contains" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="ctrls:AutoCompleteComboBox">
<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" Storyboard.TargetName="BackgroundOverlay" Storyboard.TargetProperty="Opacity" To="1"/>
<ColorAnimation Duration="0" Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[3].(GradientStop.Color)" To="#7FFFFFFF"/>
<ColorAnimation Duration="0" Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[2].(GradientStop.Color)" To="#CCFFFFFF"/>
<ColorAnimation Duration="0" Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[1].(GradientStop.Color)" To="#F2FFFFFF"/>
</Storyboard>
</VisualState>
<VisualState x:Name="Pressed">
<Storyboard>
<DoubleAnimation Duration="0" Storyboard.TargetName="BackgroundOverlay2" Storyboard.TargetProperty="Opacity" To="1"/>
<DoubleAnimation Duration="0" Storyboard.TargetName="Highlight" Storyboard.TargetProperty="(UIElement.Opacity)" To="1"/>
<ColorAnimation Duration="0" Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[1].(GradientStop.Color)" To="#E5FFFFFF"/>
<ColorAnimation Duration="0" Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[2].(GradientStop.Color)" To="#BCFFFFFF"/>
<ColorAnimation Duration="0" Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[3].(GradientStop.Color)" To="#6BFFFFFF"/>
<ColorAnimation Duration="0" Storyboard.TargetName="BackgroundGradient" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[0].(GradientStop.Color)" To="#F2FFFFFF"/>
</Storyboard>
</VisualState>
<VisualState x:Name="Disabled" />
</VisualStateGroup>
<VisualStateGroup x:Name="CheckStates">
<VisualState x:Name="Checked">
<Storyboard>
<DoubleAnimation Duration="0" Storyboard.TargetName="BackgroundOverlay3" Storyboard.TargetProperty="(UIElement.Opacity)" To="1"/>
<DoubleAnimation Duration="0" Storyboard.TargetName="Highlight" Storyboard.TargetProperty="(UIElement.Opacity)" To="1"/>
<DoubleAnimation Duration="0" Storyboard.TargetName="BackgroundGradient2" Storyboard.TargetProperty="(UIElement.Opacity)" To="1"/>
<ColorAnimation Duration="0" Storyboard.TargetName="BackgroundGradient2" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[1].(GradientStop.Color)" To="#E5FFFFFF"/>
<ColorAnimation Duration="0" Storyboard.TargetName="BackgroundGradient2" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[2].(GradientStop.Color)" To="#BCFFFFFF"/>
<ColorAnimation Duration="0" Storyboard.TargetName="BackgroundGradient2" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[3].(GradientStop.Color)" To="#6BFFFFFF"/>
<ColorAnimation Duration="0" Storyboard.TargetName="BackgroundGradient2" Storyboard.TargetProperty="(Shape.Fill).(GradientBrush.GradientStops)[0].(GradientStop.Color)" To="#F2FFFFFF"/>
</Storyboard>
</VisualState>
<VisualState x:Name="Unchecked"/>
</VisualStateGroup>
<VisualStateGroup x:Name="FocusStates">
<VisualState x:Name="Focused">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="FocusVisualElement" Storyboard.TargetProperty="Visibility" Duration="0">
<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" RadiusX="3" RadiusY="3" Fill="{TemplateBinding Background}" StrokeThickness="{TemplateBinding BorderThickness}" Stroke="{TemplateBinding BorderBrush}"/>
<Rectangle x:Name="BackgroundOverlay" Opacity="0" RadiusX="3" RadiusY="3" Fill="#FF448DCA" StrokeThickness="{TemplateBinding BorderThickness}" Stroke="#00000000"/>
<Rectangle x:Name="BackgroundOverlay2" Opacity="0" RadiusX="3" RadiusY="3" Fill="#FF448DCA" StrokeThickness="{TemplateBinding BorderThickness}" Stroke="#00000000"/>
<Rectangle x:Name="BackgroundGradient" RadiusX="2" RadiusY="2" StrokeThickness="1" Margin="{TemplateBinding BorderThickness}" Stroke="#FFFFFFFF">
<Rectangle.Fill>
<LinearGradientBrush StartPoint=".7,0" EndPoint=".7,1">
<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 Opacity="0" x:Name="BackgroundOverlay3" RadiusX="3" RadiusY="3" Fill="#FF448DCA" StrokeThickness="{TemplateBinding BorderThickness}" Stroke="#00000000"/>
<Rectangle Opacity="0" x:Name="BackgroundGradient2" RadiusX="2" RadiusY="2" StrokeThickness="1" Margin="{TemplateBinding BorderThickness}" Stroke="#FFFFFFFF">
<Rectangle.Fill>
<LinearGradientBrush StartPoint=".7,0" EndPoint=".7,1">
<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" RadiusX="2" RadiusY="2" Opacity="0" IsHitTestVisible="false" Stroke="#FF6DBDD1" StrokeThickness="1" Margin="{TemplateBinding BorderThickness}" />
<ContentPresenter
x:Name="contentPresenter"
Content="{TemplateBinding Content}"
ContentTemplate="{TemplateBinding ContentTemplate}"
HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
Margin="{TemplateBinding Padding}"/>
<Rectangle x:Name="FocusVisualElement" RadiusX="3.5" Margin="1" RadiusY="3.5" Stroke="#FF6DBDD1" StrokeThickness="1" Visibility="Collapsed" IsHitTestVisible="false" />
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<ControlTemplate x:Key="CommonValidationToolTipTemplate" TargetType="ToolTip">
<Grid x:Name="Root" Margin="5,0" RenderTransformOrigin="0,0" Opacity="0">
<Grid.RenderTransform>
<TranslateTransform x:Name="Translation" X="-25" />
</Grid.RenderTransform>
<VisualStateManager.VisualStateGroups>
<VisualStateGroup Name="OpenStates">
<VisualStateGroup.Transitions>
<VisualTransition GeneratedDuration="0" />
<VisualTransition To="Open" GeneratedDuration="0:0:0.2">
<Storyboard>
<DoubleAnimation Storyboard.TargetName="Translation" Storyboard.TargetProperty="X" To="0" Duration="0:0:0.2">
<DoubleAnimation.EasingFunction>
<BackEase Amplitude=".3" EasingMode="EaseOut" />
</DoubleAnimation.EasingFunction>
</DoubleAnimation>
<DoubleAnimation Storyboard.TargetName="Root" Storyboard.TargetProperty="Opacity" To="1" Duration="0:0:0.2" />
</Storyboard>
</VisualTransition>
</VisualStateGroup.Transitions>
<VisualState x:Name="Closed">
<Storyboard>
<DoubleAnimation Storyboard.TargetName="Root" Storyboard.TargetProperty="Opacity" To="0" Duration="0" />
</Storyboard>
</VisualState>
<VisualState x:Name="Open">
<Storyboard>
<DoubleAnimation Storyboard.TargetName="Translation" Storyboard.TargetProperty="X" To="0" Duration="0" />
<DoubleAnimation Storyboard.TargetName="Root" Storyboard.TargetProperty="Opacity" To="1" Duration="0" />
</Storyboard>
</VisualState>
</VisualStateGroup>
</VisualStateManager.VisualStateGroups>
<Border Margin="4,4,-4,-4" Background="#052A2E31" CornerRadius="5" />
<Border Margin="3,3,-3,-3" Background="#152A2E31" CornerRadius="4" />
<Border Margin="2,2,-2,-2" Background="#252A2E31" CornerRadius="3" />
<Border Margin="1,1,-1,-1" Background="#352A2E31" CornerRadius="2" />
<Border Background="#FFDC000C" CornerRadius="2">
<TextBlock UseLayoutRounding="false" Foreground="White" Margin="8,4,8,4" MaxWidth="250" TextWrapping="Wrap" Text="{Binding (Validation.Errors)[0].ErrorContent}" />
</Border>
</Grid>
</ControlTemplate>
</Grid.Resources>
<TextBox x:Name="Text" VerticalContentAlignment="Center" Background="{TemplateBinding Background}" BorderThickness="{TemplateBinding BorderThickness}" BorderBrush="{TemplateBinding BorderBrush}" Foreground="{TemplateBinding Foreground}" MaxLength="{TemplateBinding MaxLength}" />
<ToggleButton x:Name="PopupToggleButton" Width="24" HorizontalAlignment="Right" Style="{StaticResource comboToggleStyle}" Margin="1" >
<Path x:Name="BtnArrow" Height="4" Width="8" Stretch="Uniform" Data="F1 M 301.14,-189.041L 311.57,-189.041L 306.355,-182.942L 301.14,-189.041 Z " HorizontalAlignment="Center">
<Path.Fill>
<SolidColorBrush x:Name="BtnArrowColor" Color="#FF333333"/>
</Path.Fill>
</Path>
</ToggleButton>
<Border x:Name="ValidationErrorElement" Visibility="Collapsed" BorderBrush="#FFDB000C" BorderThickness="1" CornerRadius="1">
<ToolTipService.ToolTip>
<ToolTip x:Name="validationTooltip" DataContext="{Binding RelativeSource={RelativeSource TemplatedParent}}" Template="{StaticResource CommonValidationToolTipTemplate}" Placement="Right" PlacementTarget="{Binding RelativeSource={RelativeSource TemplatedParent}}">
<ToolTip.Triggers>
<EventTrigger RoutedEvent="Canvas.Loaded">
<BeginStoryboard>
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetName="validationTooltip" Storyboard.TargetProperty="IsHitTestVisible">
<DiscreteObjectKeyFrame KeyTime="0">
<DiscreteObjectKeyFrame.Value>
<system:Boolean>true</system:Boolean>
</DiscreteObjectKeyFrame.Value>
</DiscreteObjectKeyFrame>
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</BeginStoryboard>
</EventTrigger>
</ToolTip.Triggers>
</ToolTip>
</ToolTipService.ToolTip>
<Grid Height="12" HorizontalAlignment="Right" Margin="1,-4,-4,0" VerticalAlignment="Top" Width="12" Background="Transparent">
<Path Fill="#FFDC000C" Margin="1,3,0,0" Data="M 1,0 L6,0 A 2,2 90 0 1 8,2 L8,7 z" />
<Path Fill="#ffffff" Margin="1,3,0,0" Data="M 0,0 L2,0 L 8,6 L8,8" />
</Grid>
</Border>
<Popup x:Name="Popup">
<ListBox x:Name="Selector" SelectionMode="Single" ScrollViewer.HorizontalScrollBarVisibility="Disabled" ScrollViewer.VerticalScrollBarVisibility="Auto" MaxHeight="{TemplateBinding MaxDropDownHeight}" />
</Popup>
<VisualStateManager.VisualStateGroups>
<VisualStateGroup x:Name="PopupStates">
<VisualStateGroup.Transitions>
<VisualTransition GeneratedDuration="0:0:0" To="PopupOpened" />
<VisualTransition GeneratedDuration="0:0:0" To="PopupClosed" />
</VisualStateGroup.Transitions>
<VisualState x:Name="PopupOpened">
</VisualState>
<VisualState x:Name="PopupClosed">
</VisualState>
</VisualStateGroup>
<VisualStateGroup x:Name="ValidationStates">
<VisualState x:Name="Valid" />
<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>
</VisualState>
<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>
<system:Boolean>True</system:Boolean>
</DiscreteObjectKeyFrame.Value>
</DiscreteObjectKeyFrame>
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
</VisualStateGroup>
</VisualStateManager.VisualStateGroups>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
答案 1 :(得分：0)
我制定了一种方法。基本的想法是在一个修改过的控制模板中叠加一个按钮，或者只是在视图顶部抛出（为了简洁起见，我将在这里使用后者）。按钮事情做了三件事：
- 清除文本（以恢复完整的未过滤列表）
- 设置
IsDropDownOpen= true以打开弹出窗口 - 将所选项目还原到ListBox模板子项
基本上，我有这样的设置：
<Grid>
<mycontrols:ExtendedAutoCompleteBox x:Name="autoCompleteBox" ... />
<Button HorizontalAlignment="Right" Click="Button_Click">
<Path Data="F1 M 301.14,-189.041L 311.57,-189.041L 306.355,-182.942L 301.14,-189.041 Z "
Fill="Black" Stretch="Uniform"
Width="8" Height="4"
/>
</Button>
</Grid>
子类化AutoCompleteBox的目的只是为了访问模板子代：
public class ExtendedAutoCompleteBox : AutoCompleteBox
{
private ListBox _listBox;
public override void OnApplyTemplate()
{
_listBox = GetTemplateChild("Selector") as ListBox;
}
public void ShowAllOptions()
{
var selectedItem = SelectedItem;
Text = "";
IsDropDownOpen = true;
_listBox.SelectedItem = selectedItem;
UpdateLayout();
_listBox.ScrollIntoView(selectedItem);
}
}
所以点击按钮就会调用这个“ShowAllOptions”：
private void Button_Click(object sender, RoutedEventArgs e)
{
autoCompleteBox.ShowAllOptions();
}
它并不完美 - 由于某种原因，键盘控制在点击按钮后变得棘手（如果按下项目上的输入，它不会选择项目，而是清除它） - 但它总比没有好。
所以只是为了说明它的作用：假设您选择了一个项目“x”，然后单击箭头按钮，您将看到完整列表：
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