wpf 如何在代码中调用 close 之前保持 ComboBox 弹出窗口？
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How to keep ComboBox popup until I call close in the code?
提问by user1064519
I want to keep the WPF ComboBox popup until the code I wrote let it close, how can I implement this?
我想保留 WPF ComboBox 弹出窗口，直到我编写的代码让它关闭，我该如何实现？
回答by yo chauhan
ComboBox has a property IsDropDownOpenset it as True.And if you want Combobox stay open only while editing then you can set StaysOpenOnEditequal to true
ComboBox 有一个属性IsDropDownOpen将其设置为 True。如果您希望 Combobox 仅在编辑时保持打开状态，那么您可以将StaysOpenOnEdit设置为 true
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<ComboBox x:Name="cmb" IsDropDownOpen="True"/>
<Button Click="Button_Click" Content="OK" Grid.Row="2"/>
</Grid>
private void Button_Click(object sender, RoutedEventArgs e)
{
cmb.IsDropDownOpen = false;
}
<ComboBox x:Name="cmb" StaysOpenOnEdit="True"/>
I hope this will help.
我希望这将有所帮助。
回答by user1064519
Normally the property IsDropDown effects the popup,i edited the combobox template so the popup and the togglebutton who controls it- would be bined to other property -Tag
通常属性 IsDropDown 会影响弹出窗口，我编辑了组合框模板，因此弹出窗口和控制它的切换按钮 - 将绑定到其他属性 -Tag
<Style x:Key="ComboBoxStyle1" TargetType="{x:Type ComboBox}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ComboBox}">
<Grid x:Name="MainGrid" SnapsToDevicePixels="true">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition MinWidth="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}" Width="0"/>
</Grid.ColumnDefinitions>
<Popup x:Name="PART_Popup" StaysOpen="True" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding Tag, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{DynamicResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
<Microsoft_Windows_Themes:SystemDropShadowChrome x:Name="Shdw" Color="Transparent" MaxHeight="{TemplateBinding MaxDropDownHeight}" MinWidth="{Binding ActualWidth, ElementName=MainGrid}">
<Border x:Name="DropDownBorder" BorderBrush="{DynamicResource {x:Static SystemColors.WindowFrameBrushKey}}" BorderThickness="1" Background="{DynamicResource {x:Static SystemColors.WindowBrushKey}}">
<ScrollViewer x:Name="DropDownScrollViewer">
<Grid RenderOptions.ClearTypeHint="Enabled">
<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>
</Microsoft_Windows_Themes:SystemDropShadowChrome>
</Popup>
<ToggleButton BorderBrush="{TemplateBinding BorderBrush}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding Tag, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxReadonlyToggleButton}"/>
<ContentPresenter ContentTemplate="{TemplateBinding SelectionBoxItemTemplate}" ContentTemplateSelector="{TemplateBinding ItemTemplateSelector}" Content="{TemplateBinding SelectionBoxItem}" ContentStringFormat="{TemplateBinding SelectionBoxItemStringFormat}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" IsHitTestVisible="false" Margin="{TemplateBinding Padding}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="HasDropShadow" SourceName="PART_Popup" Value="true">
<Setter Property="Margin" TargetName="Shdw" Value="0,0,5,5"/>
<Setter Property="Color" TargetName="Shdw" Value="#71000000"/>
</Trigger>
<Trigger Property="HasItems" Value="false">
<Setter Property="Height" TargetName="DropDownBorder" Value="95"/>
</Trigger>
<Trigger Property="IsEnabled" Value="false">
<Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}"/>
<Setter Property="Background" Value="#FFF4F4F4"/>
</Trigger>
<Trigger Property="IsGrouping" Value="true">
<Setter Property="ScrollViewer.CanContentScroll" Value="false"/>
</Trigger>
<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>
</Setter.Value>
</Setter>
</Style>
then if you want to open\close the combobox you just need to set his Tag property to True\False :
那么如果你想打开\关闭组合框，你只需要将他的 Tag 属性设置为 True\False ：
<ComboBox Style="{DynamicResource ComboBoxStyle1}" Tag="True"/>
