Equivalent of editable ComboBox in WinRT?

Question

The standard (desktop) windows combobox has three styles; Simple, Dropdown, and Drop List. Dropdown works like an edit control and a combobox, whereas Drop List doesn't allow editing.

Am I missing something, or does the XAML ComboBox control in a Windows 8 store app only support the Drop List style?

I was halfway through implementing something when I ran into this, and the more I look, the more it seems that it just isn't supported.

Do I really need to replace the ComboBoxes in my screens with an edit control followed by a listbox?

Yuck.

Answer 1

thanks to edward.ho.tpe's answer I wrote myself a little EditableComboBox by using an TextBox inside a ComboBoxItem. If you want to use it multiple times it might be better to create a UserControl.

However this is how I did it:

The style:

<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="&#xE0A4;" 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>

The ComboBox:

<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>

The event handlers:

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;
    }
}

So basically what this is:

As edward.ho.tpe suggested a TextBox as the content of the first item of a ComboBox. The TextBox has a custom style that removes the background, the border, moves it a little to the left (optional - but i like it since it provides more space to write), and changes the delete button to stay collapsed. The SelectionChanged event handler makes sure that the TextBox stays the SelectedItem and only changes the Text based on the content of the selected item and the KeyDown event handler handles the space keydown because otherwise that would trigger the Dropdown of the ComboBox.