WPF: ComboBox senza pulsante a discesa

Question

Voglio un ComboBox che non ha un pulsante a discesa, ma può essere ancora aperto quando faccio clic sul testo nella casella combinata. E 'possibile con una combobox WPF?

Answer 1

È possibile, ma è necessario ridimensionarlo per ottenere la perfezione. È possibile ottenere la maggior parte del modo in cui ci sovrascrivendo un parametro di sistema come segue:

<ComboBox xmlns:sys="clr-namespace:System;assembly=mscorlib"> 
    <ComboBox.Resources> 
     <sys:Double x:Key="{x:Static SystemParameters.VerticalScrollBarWidthKey}">0</sys:Double> 
    </ComboBox.Resources> 
    <ComboBoxItem>One</ComboBoxItem> 
    <ComboBoxItem>Two</ComboBoxItem> 
    <ComboBoxItem>Three</ComboBoxItem> 
</ComboBox> 

Tuttavia, non è perfetto, perché il rettangolo di attivazione assume ancora c'è un pulsante presente discesa.

Answer 2

Tutti i controlli WPF sono "senza look", quindi è possibile ridefinire completamente il proprio aspetto. Tuttavia, non è semplice e ancor meno per ComboBox. ComboBox utilizza uno dei due modelli, a seconda che sia modificabile. La versione non modificabile usa ToggleButton per l'aspetto del controllo, quindi puoi semplicemente rimuovere il disegno della freccia (vedi sotto). La versione modificabile utilizza un TextBox e un ToggleButton e, se non hai ToggleButton, non si apre. Quindi, ecco un modello senza ToggleButton; spetta a te aggiungere il codice per gestire i clic sul modello modificabile. (Oppure, se non hai bisogno di modificare, puoi forzare IsEditable a false e farlo.)

Avvertenza: questo è il modello Aero e utilizza il chrome Aero, quindi non verrà visualizzato in altri temi . Affinché ciò accada, è necessario estrarre i modelli per ciascun tema e apportare le modifiche appropriate oppure rimuovere il cromo del tema e disegnare i propri bordi.

Aggiungi questa definizione dello spazio dei nomi e aggiungere un riferimento a PresentationFramework.Aero:

xmlns:t="clr-namespace:Microsoft.Windows.Themes;assembly=PresentationFramework.Aero" 

quindi aggiungere il seguente alla finestra/risorse di controllo:

<Style x:Key="ComboBoxFocusVisual"> 
     <Setter Property="Control.Template"> 
      <Setter.Value> 
       <ControlTemplate> 
        <Rectangle Stroke="Black" StrokeDashArray="1 2" StrokeThickness="1" Margin="4,4,21,4" SnapsToDevicePixels="true"/> 
       </ControlTemplate> 
      </Setter.Value> 
     </Setter> 
    </Style> 
    <LinearGradientBrush x:Key="ButtonNormalBackground" EndPoint="0,1" StartPoint="0,0"> 
     <GradientStop Color="#F3F3F3" Offset="0"/> 
     <GradientStop Color="#EBEBEB" Offset="0.5"/> 
     <GradientStop Color="#DDDDDD" Offset="0.5"/> 
     <GradientStop Color="#CDCDCD" Offset="1"/> 
    </LinearGradientBrush> 
    <SolidColorBrush x:Key="ButtonNormalBorder" Color="#FF707070"/> 
    <Geometry x:Key="DownArrowGeometry">M 0 0 L 3.5 4 L 7 0 Z</Geometry> 
    <Style x:Key="ComboBoxReadonlyToggleButton" 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}"> 
        <t:ButtonChrome x:Name="Chrome" SnapsToDevicePixels="true" Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}" RenderMouseOver="{TemplateBinding IsMouseOver}" RenderPressed="{TemplateBinding IsPressed}"> 
         <!-- Remove ToggleButton appearance; we still need the ToggleButton because it displays the content. 
         <Grid HorizontalAlignment="Right" Width="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}"> 
          <Path x:Name="Arrow" Fill="Black" HorizontalAlignment="Center" Margin="3,1,0,0" VerticalAlignment="Center" Data="{StaticResource DownArrowGeometry}"/> 
         </Grid> 
         --> 
        </t:ButtonChrome> 
        <ControlTemplate.Triggers> 
         <Trigger Property="IsChecked" Value="true"> 
          <Setter Property="RenderPressed" TargetName="Chrome" Value="true"/> 
         </Trigger> 
         <!-- Remove ToggleButton appearance trigger 
         <Trigger Property="IsEnabled" Value="false"> 
          <Setter Property="Fill" TargetName="Arrow" Value="#AFAFAF"/> 
         </Trigger> 
         --> 
        </ControlTemplate.Triggers> 
       </ControlTemplate> 
      </Setter.Value> 
     </Setter> 
    </Style> 
    <LinearGradientBrush x:Key="TextBoxBorder" EndPoint="0,20" StartPoint="0,0" MappingMode="Absolute"> 
     <GradientStop Color="#ABADB3" Offset="0.05"/> 
     <GradientStop Color="#E2E3EA" Offset="0.07"/> 
     <GradientStop Color="#E3E9EF" Offset="1"/> 
    </LinearGradientBrush> 
    <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="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> 
    <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}"> 
        <t:ButtonChrome x:Name="Chrome" Width="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}" SnapsToDevicePixels="true" Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}" RenderMouseOver="{TemplateBinding IsMouseOver}" RenderPressed="{TemplateBinding IsPressed}" RoundCorners="false"> 
         <Path x:Name="Arrow" Fill="Black" HorizontalAlignment="Center" Margin="0,1,0,0" VerticalAlignment="Center" Data="{StaticResource DownArrowGeometry}"/> 
        </t:ButtonChrome> 
        <ControlTemplate.Triggers> 
         <Trigger Property="IsChecked" Value="true"> 
          <Setter Property="RenderPressed" TargetName="Chrome" Value="true"/> 
         </Trigger> 
         <Trigger Property="IsEnabled" Value="false"> 
          <Setter Property="Fill" TargetName="Arrow" Value="#AFAFAF"/> 
         </Trigger> 
        </ControlTemplate.Triggers> 
       </ControlTemplate> 
      </Setter.Value> 
     </Setter> 
    </Style> 
    <ControlTemplate x:Key="ComboBoxEditableTemplate" TargetType="{x:Type ComboBox}"> 
     <Grid x:Name="Placement" SnapsToDevicePixels="true"> 
      <Grid.ColumnDefinitions> 
       <ColumnDefinition Width="*"/> 
       <ColumnDefinition Width="Auto"/> 
      </Grid.ColumnDefinitions> 
      <Popup x:Name="PART_Popup" AllowsTransparency="true" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" Placement="Bottom" PopupAnimation="{DynamicResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Grid.ColumnSpan="2"> 
       <t:SystemDropShadowChrome x:Name="Shdw" MaxHeight="{TemplateBinding MaxDropDownHeight}" MinWidth="{Binding ActualWidth, ElementName=Placement}" Color="Transparent"> 
        <Border x:Name="DropDownBorder" Background="{DynamicResource {x:Static SystemColors.WindowBrushKey}}" BorderBrush="{DynamicResource {x:Static SystemColors.WindowFrameBrushKey}}" BorderThickness="1"> 
         <ScrollViewer> 
          <ItemsPresenter SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" KeyboardNavigation.DirectionalNavigation="Contained"/> 
         </ScrollViewer> 
        </Border> 
       </t:SystemDropShadowChrome> 
      </Popup> 
      <t:ListBoxChrome x:Name="Border" Grid.ColumnSpan="2" Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" RenderFocused="{TemplateBinding IsKeyboardFocusWithin}" RenderMouseOver="{TemplateBinding IsMouseOver}"/> 
      <TextBox x:Name="PART_EditableTextBox" Margin="{TemplateBinding Padding}" Style="{StaticResource ComboBoxEditableTextBox}" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}" IsReadOnly="{Binding IsReadOnly, RelativeSource={RelativeSource TemplatedParent}}"/> 
      <!-- Remove the ToggleButton button; now you make the textbox clickable.... 
       <ToggleButton Style="{StaticResource ComboBoxToggleButton}" Grid.Column="1" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}"/> 
      --> 
     </Grid> 
     <ControlTemplate.Triggers> 
      <Trigger Property="IsKeyboardFocusWithin" Value="true"> 
       <Setter Property="Foreground" Value="Black"/> 
      </Trigger> 
      <Trigger Property="IsDropDownOpen" Value="true"> 
       <Setter Property="RenderFocused" TargetName="Border" Value="true"/> 
      </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="HasDropShadow" SourceName="PART_Popup" Value="true"> 
       <Setter Property="Margin" TargetName="Shdw" Value="0,0,5,5"/> 
       <Setter Property="Color" TargetName="Shdw" Value="#71000000"/> 
      </Trigger> 
     </ControlTemplate.Triggers> 
    </ControlTemplate> 
    <Style x:Key="ButtonlessComboBoxStyle" TargetType="{x:Type ComboBox}"> 
     <Setter Property="FocusVisualStyle" Value="{StaticResource ComboBoxFocusVisual}"/> 
     <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.WindowTextBrushKey}}"/> 
     <Setter Property="Background" Value="{StaticResource ButtonNormalBackground}"/> 
     <Setter Property="BorderBrush" Value="{StaticResource ButtonNormalBorder}"/> 
     <Setter Property="BorderThickness" Value="1"/> 
     <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Auto"/> 
     <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto"/> 
     <Setter Property="Padding" Value="4,3"/> 
     <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" Margin="1" AllowsTransparency="true" IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}}" Placement="Bottom" PopupAnimation="{DynamicResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Grid.ColumnSpan="2"> 
          <t:SystemDropShadowChrome x:Name="Shdw" MaxHeight="{TemplateBinding MaxDropDownHeight}" MinWidth="{Binding ActualWidth, ElementName=MainGrid}" Color="Transparent"> 
           <Border x:Name="DropDownBorder" Background="{DynamicResource {x:Static SystemColors.WindowBrushKey}}" BorderBrush="{DynamicResource {x:Static SystemColors.WindowFrameBrushKey}}" BorderThickness="1"> 
            <ScrollViewer CanContentScroll="true"> 
             <ItemsPresenter SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" KeyboardNavigation.DirectionalNavigation="Contained"/> 
            </ScrollViewer> 
           </Border> 
          </t:SystemDropShadowChrome> 
         </Popup> 
         <ToggleButton Style="{StaticResource ComboBoxReadonlyToggleButton}" Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}" Grid.ColumnSpan="2" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}"/> 
         <ContentPresenter HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" IsHitTestVisible="false" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" Content="{TemplateBinding SelectionBoxItem}" ContentStringFormat="{TemplateBinding SelectionBoxItemStringFormat}" ContentTemplate="{TemplateBinding SelectionBoxItemTemplate}" ContentTemplateSelector="{TemplateBinding ItemTemplateSelector}"/> 
        </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> 
        </ControlTemplate.Triggers> 
       </ControlTemplate> 
      </Setter.Value> 
     </Setter> 
     <Style.Triggers> 
      <Trigger Property="IsEditable" Value="true"> 
       <Setter Property="BorderBrush" Value="{StaticResource TextBoxBorder}"/> 
       <Setter Property="Background" Value="{DynamicResource {x:Static SystemColors.WindowBrushKey}}"/> 
       <Setter Property="IsTabStop" Value="false"/> 
       <Setter Property="Padding" Value="3"/> 
       <Setter Property="Template" Value="{StaticResource ComboBoxEditableTemplate}"/> 
      </Trigger> 
     </Style.Triggers> 
    </Style> 

Quindi utilizzare:

<ComboBox HorizontalAlignment="Left" Width="120" Style="{DynamicResource ButtonlessComboBoxStyle}"> 
    <ComboBox.Items> 
     <ComboBoxItem>One</ComboBoxItem> 
     <ComboBoxItem>Two</ComboBoxItem> 
     <ComboBoxItem>Three</ComboBoxItem> 
    </ComboBox.Items> 
</ComboBox> 

<ComboBox HorizontalAlignment="Left" Width="120" IsEditable="True" Style="{DynamicResource ButtonlessComboBoxStyle}"> 
    <ComboBox.Items> 
     <ComboBoxItem>One</ComboBoxItem> 
     <ComboBoxItem>Two</ComboBoxItem> 
     <ComboBoxItem>Three</ComboBoxItem> 
    </ComboBox.Items> 
</ComboBox> 

Nota: gli stili sono indicati come DynamicResource perché si basano sul tema chrome, quindi devono rispondere ai cambiamenti nello stile visivo del sistema operativo. Se rimuovi il chrome e utilizzi i bordi WPF, dovresti fare riferimento a questi come StaticResource per le prestazioni.