Question

我希望能够在ComboBox中选择一个值，但要避免所选的值更新。

换句话说，对于上图，我希望在选择其中一个项目时，空选择保持为空。

我尝试了大量不同的解决方案 - SelectedIndex，SelectedValue，SelectionChanged上的各种绑定，使用IsEditable，IsReadonly，{{ 1}}，IsHitTestVisible等等，等等。

如何防止组合框在选择时自动更新文本，但是仍然可以选择一个选项？

示例代码：

Text

Answer 1

这是我想出的基于向组合框添加按钮的东西。

这只是添加到组合框中的两个按钮。

    <ComboBox x:Name="cboBox" HorizontalAlignment="Left" VerticalAlignment="Top" Width="151" Margin="182,132,0,0" SelectionChanged="cboBox_SelectionChanged" Grid.Column="1" Height="22">
        <Button Content="Close" Width="141" Click="Button_Close" Height="51"/>
        <Button Content="Delete" Width="141" Click="Button_Delete" Height="51"/>
    </ComboBox>

然后我进入后面的代码并添加了代码来处理每个按钮的click事件。

正如您将看到我们甚至没有处理组合框，除了使用它来显示按钮，然后在单击其中一个按钮时关闭下拉列表。

    private void Button_Close(object sender, RoutedEventArgs e)
    {
        lbl1.Content = "Close Clicked";
        cboBox.IsDropDownOpen = false;
    }

    private void Button_Delete(object sender, RoutedEventArgs e)
    {
        lbl1.Content = "Delete Clicked";
        cboBox.IsDropDownOpen = false;
    }

我真的需要更好地掌握WPF。我真的很喜欢弄乱这个。

Answer 2

作为一名经验丰富的WPF开发人员，我会对这个问题有所了解。基本上，您已经使用错误的仪器尝试了大量不同的解决方案。

在WPF中，每个控件都有一个默认样式，它完全描述了你在屏幕上看到的内容（这里没有任何隐藏）。然而，不那么明显的是如何看一下控件的默认样式。（我使用VS 2013，但下面描述的步骤也适用于更高版本）

在'Blend for Visual Studio 2013
在“资产”标签搜索框中输入“ComboBox”并双击它
右键单击刚刚在“对象和时间轴”面板中添加的ComboBox，然后选择“编辑模板 - ＆gt;编辑副本...”
切换到代码视图（按钮位于右上角）

是的，默认样式非常冗长！

现在，我们感兴趣的是ControlTemplate。此临时板中必须有一些控件负责显示所选项目。如果你赶时间，只需找到它并删除适当的绑定。下面是一个示例解决方案，我称之为“截止日期解决方案之前的几小时”。阅读XAML中的注释以获得正确的方法。

<Window x:Class="ComboBoxAdventures.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:Themes="clr-namespace:Microsoft.Windows.Themes;assembly=PresentationFramework.Aero2"
        Title="MainWindow" Height="350" Width="525">
    <Window.Resources>
        <Style x:Key="FocusVisual">
            <Setter Property="Control.Template">
                <Setter.Value>
                    <ControlTemplate>
                        <Rectangle Margin="2" SnapsToDevicePixels="true" Stroke="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}" StrokeThickness="1" StrokeDashArray="1 2"/>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
        <LinearGradientBrush x:Key="ComboBox.Static.Background" EndPoint="0,1" StartPoint="0,0">
            <GradientStop Color="#FFF0F0F0" Offset="0.0"/>
            <GradientStop Color="#FFE5E5E5" Offset="1.0"/>
        </LinearGradientBrush>
        <SolidColorBrush x:Key="ComboBox.Static.Border" Color="#FFACACAC"/>
        <SolidColorBrush x:Key="ComboBox.Static.Editable.Background" Color="#FFFFFFFF"/>
        <SolidColorBrush x:Key="ComboBox.Static.Editable.Border" Color="#FFABADB3"/>
        <SolidColorBrush x:Key="ComboBox.Static.Editable.Button.Background" Color="Transparent"/>
        <SolidColorBrush x:Key="ComboBox.Static.Editable.Button.Border" Color="Transparent"/>
        <SolidColorBrush x:Key="ComboBox.MouseOver.Glyph" Color="#FF000000"/>
        <LinearGradientBrush x:Key="ComboBox.MouseOver.Background" EndPoint="0,1" StartPoint="0,0">
            <GradientStop Color="#FFECF4FC" Offset="0.0"/>
            <GradientStop Color="#FFDCECFC" Offset="1.0"/>
        </LinearGradientBrush>
        <SolidColorBrush x:Key="ComboBox.MouseOver.Border" Color="#FF7EB4EA"/>
        <SolidColorBrush x:Key="ComboBox.MouseOver.Editable.Background" Color="#FFFFFFFF"/>
        <SolidColorBrush x:Key="ComboBox.MouseOver.Editable.Border" Color="#FF7EB4EA"/>
        <LinearGradientBrush x:Key="ComboBox.MouseOver.Editable.Button.Background" EndPoint="0,1" StartPoint="0,0">
            <GradientStop Color="#FFEBF4FC" Offset="0.0"/>
            <GradientStop Color="#FFDCECFC" Offset="1.0"/>
        </LinearGradientBrush>
        <SolidColorBrush x:Key="ComboBox.MouseOver.Editable.Button.Border" Color="#FF7EB4EA"/>
        <SolidColorBrush x:Key="ComboBox.Pressed.Glyph" Color="#FF000000"/>
        <LinearGradientBrush x:Key="ComboBox.Pressed.Background" EndPoint="0,1" StartPoint="0,0">
            <GradientStop Color="#FFDAECFC" Offset="0.0"/>
            <GradientStop Color="#FFC4E0FC" Offset="1.0"/>
        </LinearGradientBrush>
        <SolidColorBrush x:Key="ComboBox.Pressed.Border" Color="#FF569DE5"/>
        <SolidColorBrush x:Key="ComboBox.Pressed.Editable.Background" Color="#FFFFFFFF"/>
        <SolidColorBrush x:Key="ComboBox.Pressed.Editable.Border" Color="#FF569DE5"/>
        <LinearGradientBrush x:Key="ComboBox.Pressed.Editable.Button.Background" EndPoint="0,1" StartPoint="0,0">
            <GradientStop Color="#FFDAEBFC" Offset="0.0"/>
            <GradientStop Color="#FFC4E0FC" Offset="1.0"/>
        </LinearGradientBrush>
        <SolidColorBrush x:Key="ComboBox.Pressed.Editable.Button.Border" Color="#FF569DE5"/>
        <SolidColorBrush x:Key="ComboBox.Disabled.Glyph" Color="#FFBFBFBF"/>
        <SolidColorBrush x:Key="ComboBox.Disabled.Background" Color="#FFF0F0F0"/>
        <SolidColorBrush x:Key="ComboBox.Disabled.Border" Color="#FFD9D9D9"/>
        <SolidColorBrush x:Key="ComboBox.Disabled.Editable.Background" Color="#FFFFFFFF"/>
        <SolidColorBrush x:Key="ComboBox.Disabled.Editable.Border" Color="#FFBFBFBF"/>
        <SolidColorBrush x:Key="ComboBox.Disabled.Editable.Button.Background" Color="Transparent"/>
        <SolidColorBrush x:Key="ComboBox.Disabled.Editable.Button.Border" Color="Transparent"/>
        <SolidColorBrush x:Key="ComboBox.Static.Glyph" Color="#FF606060"/>
        <Style x:Key="ComboBoxToggleButton" TargetType="{x:Type ToggleButton}">
            <Setter Property="OverridesDefaultStyle" Value="true"/>
            <Setter Property="IsTabStop" Value="false"/>
            <Setter Property="Focusable" Value="false"/>
            <Setter Property="ClickMode" Value="Press"/>
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type ToggleButton}">
                        <Border x:Name="templateRoot" BorderBrush="{StaticResource ComboBox.Static.Border}" BorderThickness="{TemplateBinding BorderThickness}" Background="{StaticResource ComboBox.Static.Background}" SnapsToDevicePixels="true">
                            <Border x:Name="splitBorder" BorderBrush="Transparent" BorderThickness="1" HorizontalAlignment="Right" Margin="0" SnapsToDevicePixels="true" Width="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}">
                                <Path x:Name="arrow" Data="F1 M 0,0 L 2.667,2.66665 L 5.3334,0 L 5.3334,-1.78168 L 2.6667,0.88501 L0,-1.78168 L0,0 Z" Fill="{StaticResource ComboBox.Static.Glyph}" HorizontalAlignment="Center" Margin="0" VerticalAlignment="Center"/>
                            </Border>
                        </Border>
                        <ControlTemplate.Triggers>
                            <MultiDataTrigger>
                                <MultiDataTrigger.Conditions>
                                    <Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="true"/>
                                    <Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="false"/>
                                    <Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="false"/>
                                    <Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="true"/>
                                </MultiDataTrigger.Conditions>
                                <Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Static.Editable.Background}"/>
                                <Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.Static.Editable.Border}"/>
                                <Setter Property="Background" TargetName="splitBorder" Value="{StaticResource ComboBox.Static.Editable.Button.Background}"/>
                                <Setter Property="BorderBrush" TargetName="splitBorder" Value="{StaticResource ComboBox.Static.Editable.Button.Border}"/>
                            </MultiDataTrigger>
                            <Trigger Property="IsMouseOver" Value="true">
                                <Setter Property="Fill" TargetName="arrow" Value="{StaticResource ComboBox.MouseOver.Glyph}"/>
                            </Trigger>
                            <MultiDataTrigger>
                                <MultiDataTrigger.Conditions>
                                    <Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="true"/>
                                    <Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="false"/>
                                </MultiDataTrigger.Conditions>
                                <Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.MouseOver.Background}"/>
                                <Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.MouseOver.Border}"/>
                            </MultiDataTrigger>
                            <MultiDataTrigger>
                                <MultiDataTrigger.Conditions>
                                    <Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="true"/>
                                    <Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="true"/>
                                </MultiDataTrigger.Conditions>
                                <Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.MouseOver.Editable.Background}"/>
                                <Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.MouseOver.Editable.Border}"/>
                                <Setter Property="Background" TargetName="splitBorder" Value="{StaticResource ComboBox.MouseOver.Editable.Button.Background}"/>
                                <Setter Property="BorderBrush" TargetName="splitBorder" Value="{StaticResource ComboBox.MouseOver.Editable.Button.Border}"/>
                            </MultiDataTrigger>
                            <Trigger Property="IsPressed" Value="true">
                                <Setter Property="Fill" TargetName="arrow" Value="{StaticResource ComboBox.Pressed.Glyph}"/>
                            </Trigger>
                            <MultiDataTrigger>
                                <MultiDataTrigger.Conditions>
                                    <Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="true"/>
                                    <Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="false"/>
                                </MultiDataTrigger.Conditions>
                                <Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Pressed.Background}"/>
                                <Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.Pressed.Border}"/>
                            </MultiDataTrigger>
                            <MultiDataTrigger>
                                <MultiDataTrigger.Conditions>
                                    <Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="true"/>
                                    <Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="true"/>
                                </MultiDataTrigger.Conditions>
                                <Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Pressed.Editable.Background}"/>
                                <Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.Pressed.Editable.Border}"/>
                                <Setter Property="Background" TargetName="splitBorder" Value="{StaticResource ComboBox.Pressed.Editable.Button.Background}"/>
                                <Setter Property="BorderBrush" TargetName="splitBorder" Value="{StaticResource ComboBox.Pressed.Editable.Button.Border}"/>
                            </MultiDataTrigger>
                            <Trigger Property="IsEnabled" Value="false">
                                <Setter Property="Fill" TargetName="arrow" Value="{StaticResource ComboBox.Disabled.Glyph}"/>
                            </Trigger>
                            <MultiDataTrigger>
                                <MultiDataTrigger.Conditions>
                                    <Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="false"/>
                                    <Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="false"/>
                                </MultiDataTrigger.Conditions>
                                <Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Disabled.Background}"/>
                                <Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.Disabled.Border}"/>
                            </MultiDataTrigger>
                            <MultiDataTrigger>
                                <MultiDataTrigger.Conditions>
                                    <Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="false"/>
                                    <Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}" Value="true"/>
                                </MultiDataTrigger.Conditions>
                                <Setter Property="Background" TargetName="templateRoot" Value="{StaticResource ComboBox.Disabled.Editable.Background}"/>
                                <Setter Property="BorderBrush" TargetName="templateRoot" Value="{StaticResource ComboBox.Disabled.Editable.Border}"/>
                                <Setter Property="Background" TargetName="splitBorder" Value="{StaticResource ComboBox.Disabled.Editable.Button.Background}"/>
                                <Setter Property="BorderBrush" TargetName="splitBorder" Value="{StaticResource ComboBox.Disabled.Editable.Button.Border}"/>
                            </MultiDataTrigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
        <ControlTemplate x:Key="ComboBoxTemplate" TargetType="{x:Type ComboBox}">
            <Grid x:Name="templateRoot" SnapsToDevicePixels="true">
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="*"/>
                    <ColumnDefinition MinWidth="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}" Width="0"/>
                </Grid.ColumnDefinitions>
                <Popup x:Name="PART_Popup" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{DynamicResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                    <Themes:SystemDropShadowChrome x:Name="shadow" Color="Transparent" MaxHeight="{TemplateBinding MaxDropDownHeight}" MinWidth="{Binding ActualWidth, ElementName=templateRoot}">
                        <Border x:Name="dropDownBorder" BorderBrush="{DynamicResource {x:Static SystemColors.WindowFrameBrushKey}}" BorderThickness="1" Background="{DynamicResource {x:Static SystemColors.WindowBrushKey}}">
                            <ScrollViewer x:Name="DropDownScrollViewer">
                                <Grid x:Name="grid" RenderOptions.ClearTypeHint="Enabled">
                                    <Canvas x:Name="canvas" HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
                                        <Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
                                    </Canvas>
                                    <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
                                </Grid>
                            </ScrollViewer>
                        </Border>
                    </Themes:SystemDropShadowChrome>
                </Popup>
                <ToggleButton x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxToggleButton}"/>
                <!-- This content presenter displays the selected item.
                     The easiest way is just to remove the Content binding as shown below.
                     The proper way to do those kind of things, however, is to inherit from ComboBox,
                     define a dependency property ShowSelectedItem and then add a trigger for the ContentPreseneter below,
                     which changes the Content based on the value of the ShowSelectedItem.
                     You'll also need a custom IValueConverter for mapping bool to Hidden/Visible and some
                     googling about Generic.xaml and how to overwrite the DefaultStyle dependency property in the static constructor.

                     You may also wonder why I didn't just comment out the whole ContentPresenter.
                     Well, lets say it just keeps the 'backbone' of the control :)
                -->
                <ContentPresenter x:Name="contentPresenter" Tag="I have removed only this part: Content='{TemplateBinding SelectionBoxItem}'"
                                  ContentTemplate="{TemplateBinding SelectionBoxItemTemplate}" 
                                  ContentTemplateSelector="{TemplateBinding ItemTemplateSelector}" 
                                  Content="" ContentStringFormat="{TemplateBinding SelectionBoxItemStringFormat}" 
                                  HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" 
                                  IsHitTestVisible="false" Margin="{TemplateBinding Padding}" 
                                  SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" 
                                  VerticalAlignment="{TemplateBinding VerticalContentAlignment}">
                </ContentPresenter>
            </Grid>
            <ControlTemplate.Triggers>
                <Trigger Property="HasDropShadow" SourceName="PART_Popup" Value="true">
                    <Setter Property="Margin" TargetName="shadow" Value="0,0,5,5"/>
                    <Setter Property="Color" TargetName="shadow" Value="#71000000"/>
                </Trigger>
                <Trigger Property="HasItems" Value="false">
                    <Setter Property="Height" TargetName="dropDownBorder" Value="95"/>
                </Trigger>
                <MultiTrigger>
                    <MultiTrigger.Conditions>
                        <Condition Property="IsGrouping" Value="true"/>
                        <Condition Property="VirtualizingPanel.IsVirtualizingWhenGrouping" Value="false"/>
                    </MultiTrigger.Conditions>
                    <Setter Property="ScrollViewer.CanContentScroll" Value="false"/>
                </MultiTrigger>
                <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
                    <Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
                    <Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
                </Trigger>
            </ControlTemplate.Triggers>
        </ControlTemplate>
        <SolidColorBrush x:Key="TextBox.Static.Background" Color="#FFFFFFFF"/>
        <Style x:Key="ComboBoxEditableTextBox" TargetType="{x:Type TextBox}">
            <Setter Property="OverridesDefaultStyle" Value="true"/>
            <Setter Property="AllowDrop" Value="true"/>
            <Setter Property="MinWidth" Value="0"/>
            <Setter Property="MinHeight" Value="0"/>
            <Setter Property="FocusVisualStyle" Value="{x:Null}"/>
            <Setter Property="ScrollViewer.PanningMode" Value="VerticalFirst"/>
            <Setter Property="Stylus.IsFlicksEnabled" Value="False"/>
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type TextBox}">
                        <ScrollViewer x:Name="PART_ContentHost" Background="Transparent" Focusable="false" HorizontalScrollBarVisibility="Hidden" VerticalScrollBarVisibility="Hidden"/>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
        <ControlTemplate x:Key="ComboBoxEditableTemplate" TargetType="{x:Type ComboBox}">
            <Grid x:Name="templateRoot" SnapsToDevicePixels="true">
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="*"/>
                    <ColumnDefinition MinWidth="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}" Width="0"/>
                </Grid.ColumnDefinitions>
                <Popup x:Name="PART_Popup" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" PopupAnimation="{DynamicResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                    <Themes:SystemDropShadowChrome x:Name="shadow" Color="Transparent" MaxHeight="{TemplateBinding MaxDropDownHeight}" MinWidth="{Binding ActualWidth, ElementName=templateRoot}">
                        <Border x:Name="dropDownBorder" BorderBrush="{DynamicResource {x:Static SystemColors.WindowFrameBrushKey}}" BorderThickness="1" Background="{DynamicResource {x:Static SystemColors.WindowBrushKey}}">
                            <ScrollViewer x:Name="DropDownScrollViewer">
                                <Grid x:Name="grid" RenderOptions.ClearTypeHint="Enabled">
                                    <Canvas x:Name="canvas" HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
                                        <Rectangle x:Name="opaqueRect" Fill="{Binding Background, ElementName=dropDownBorder}" Height="{Binding ActualHeight, ElementName=dropDownBorder}" Width="{Binding ActualWidth, ElementName=dropDownBorder}"/>
                                    </Canvas>
                                    <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
                                </Grid>
                            </ScrollViewer>
                        </Border>
                    </Themes:SystemDropShadowChrome>
                </Popup>
                <ToggleButton x:Name="toggleButton" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxToggleButton}"/>
                <Border x:Name="border" Background="{StaticResource TextBox.Static.Background}" Margin="{TemplateBinding BorderThickness}">
                    <TextBox x:Name="PART_EditableTextBox" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" IsReadOnly="{Binding IsReadOnly, RelativeSource={RelativeSource TemplatedParent}}" Margin="{TemplateBinding Padding}" Style="{StaticResource ComboBoxEditableTextBox}" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"/>
                </Border>
            </Grid>
            <ControlTemplate.Triggers>
                <Trigger Property="IsEnabled" Value="false">
                    <Setter Property="Opacity" TargetName="border" Value="0.56"/>
                </Trigger>
                <Trigger Property="IsKeyboardFocusWithin" Value="true">
                    <Setter Property="Foreground" Value="Black"/>
                </Trigger>
                <Trigger Property="HasDropShadow" SourceName="PART_Popup" Value="true">
                    <Setter Property="Margin" TargetName="shadow" Value="0,0,5,5"/>
                    <Setter Property="Color" TargetName="shadow" Value="#71000000"/>
                </Trigger>
                <Trigger Property="HasItems" Value="false">
                    <Setter Property="Height" TargetName="dropDownBorder" Value="95"/>
                </Trigger>
                <MultiTrigger>
                    <MultiTrigger.Conditions>
                        <Condition Property="IsGrouping" Value="true"/>
                        <Condition Property="VirtualizingPanel.IsVirtualizingWhenGrouping" Value="false"/>
                    </MultiTrigger.Conditions>
                    <Setter Property="ScrollViewer.CanContentScroll" Value="false"/>
                </MultiTrigger>
                <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
                    <Setter Property="Canvas.Top" TargetName="opaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
                    <Setter Property="Canvas.Left" TargetName="opaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
                </Trigger>
            </ControlTemplate.Triggers>
        </ControlTemplate>
        <Style x:Key="Style.ComboBox.Ghost" TargetType="{x:Type ComboBox}">
            <Setter Property="FocusVisualStyle" Value="{StaticResource FocusVisual}"/>
            <Setter Property="Background" Value="{StaticResource ComboBox.Static.Background}"/>
            <Setter Property="BorderBrush" Value="{StaticResource ComboBox.Static.Border}"/>
            <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.WindowTextBrushKey}}"/>
            <Setter Property="BorderThickness" Value="1"/>
            <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Auto"/>
            <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto"/>
            <Setter Property="Padding" Value="6,3,5,3"/>
            <Setter Property="ScrollViewer.CanContentScroll" Value="true"/>
            <Setter Property="ScrollViewer.PanningMode" Value="Both"/>
            <Setter Property="Stylus.IsFlicksEnabled" Value="False"/>
            <Setter Property="Template" Value="{StaticResource ComboBoxTemplate}"/>
            <Style.Triggers>
                <Trigger Property="IsEditable" Value="true">
                    <Setter Property="IsTabStop" Value="false"/>
                    <Setter Property="Padding" Value="2"/>
                    <Setter Property="Template" Value="{StaticResource ComboBoxEditableTemplate}"/>
                </Trigger>
            </Style.Triggers>
        </Style>
    </Window.Resources>
    <StackPanel>
        <ComboBox Style="{StaticResource Style.ComboBox.Ghost}" ItemsSource="{Binding SelectedDummyModel}" SelectedItem="{Binding DummyModels}"/>
    </StackPanel>
</Window>

WPF组合框防止选择更新

2 个答案: