How to change the grey default background of a combobox in wpf in xaml

VFarkas 30 Reputation points
2024-02-02T20:36:18.67+00:00

Hi how can I change the grey default background color of a combobox? Of the selected Item not the dropdown list Any help?

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Accepted answer
  1. Hui Liu-MSFT 47,256 Reputation points Microsoft Vendor
    2024-02-05T05:53:45.5433333+00:00

    Hi,@ VFarkas. Welcome to Microsoft Q&A forum.

    Get the default style of the Combobox: In the Designer -> Right Click the ComboBox -> Edit Template -> Edit a Copy

    It can be changed by modifying the default template.

    The complete code:

    
     <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">
                                        <Grid.ColumnDefinitions>
                                            <ColumnDefinition Width="13*"/>
                                            <ColumnDefinition Width="41*"/>
                                        </Grid.ColumnDefinitions>
                                        <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.ColumnSpan="2"/>
                                    </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}"/>
                    <ContentPresenter x:Name="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="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="Yellow"/>
            <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" Background="{StaticResource TextBox.Static.Background}" 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="ComboBoxStyle1" 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>
        <Grid>
            <ComboBox x:Name="combo_ftpdia" Width="110" Height="20" Margin="10 5 10 0" IsEditable="True"
                      VerticalContentAlignment="Center" Style="{StaticResource ComboBoxStyle1}" >
                <ComboBoxItem Content="C:\"/>
                <ComboBoxItem Content="D:\"/>
                <ComboBoxItem Content="E:\"/>
            </ComboBox>
        </Grid>
    
    

    The result: 208741-image.png


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1 additional answer

Sort by: Most helpful
  1. Andy De George 90 Reputation points Microsoft Employee
    2024-02-02T21:28:18.2066667+00:00

    Using Bing CoPilot AI chat with the question "How do I change the background of a selected item in a combobox for wpf" seemed to have worked and generated steps and a theme that worked. However, styling in WPF can be complicated. Here's the answer it gave me, which I tweaked to add the IsMouseOver trigger.

    <Window.Resources>
        <Style x:Key="MyComboBoxItemStyle" TargetType="{x:Type ComboBoxItem}">
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type ComboBoxItem}">
                        <Border x:Name="myBorder">
                            <ContentPresenter />
                        </Border>
                        <ControlTemplate.Triggers>
                            <Trigger Property="IsSelected" Value="True">
                                <Setter TargetName="myBorder" Property="Background" Value="Violet" />
                            </Trigger>
                            <Trigger Property="IsMouseOver" Value="True">
                                <Setter TargetName="myBorder" Property="Background" Value="LightBlue" />
                            </Trigger>
                        </ControlTemplate.Triggers> 
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </Window.Resources>
    

    In your combobox, set the ItemContainerStyle to that style:

    <ComboBox ItemContainerStyle="{StaticResource MyComboBoxItemStyle}">
        <ComboBox.Items>
            <ComboBoxItem Content="Item 1" />
            <ComboBoxItem Content="Item 2" />
            <ComboBoxItem Content="Item 3" />
            <ComboBoxItem Content="Item 4" />
            <ComboBoxItem Content="Item 5" />
            <ComboBoxItem Content="Item 6" />
        </ComboBox.Items>
    </ComboBox>
    

    However, if you want a comprehensive style, you'll need to jump into Blend, so open the project in Blend. With NO style applied to the ItemContainerStyle property, go to the Objects and Timeline window and right-click on the ComboBox. Select:

    1. Edit Additional Templates
    2. Edit Generated Item Container (Item Container Style)
    3. Edit a Copy... and save that to a file or the current window.

    This creates an exact copy of the current style. If no none applied, then it's a copy of the default style. In the default style, notice this block of colors. You can edit those colors while keeping the functionality of the entire style intact.

    <SolidColorBrush x:Key="ComboBoxItem.ItemsviewHover.Background" Color="#1F26A0DA"/>
    <SolidColorBrush x:Key="ComboBoxItem.ItemsviewHover.Border" Color="#A826A0DA"/>
    <SolidColorBrush x:Key="ComboBoxItem.ItemsviewSelected.Background" Color="#3D26A0DA"/>
    <SolidColorBrush x:Key="ComboBoxItem.ItemsviewSelected.Border" Color="#FF26A0DA"/>
    <SolidColorBrush x:Key="ComboBoxItem.ItemsviewSelectedHover.Background" Color="#2E0080FF"/>
    <SolidColorBrush x:Key="ComboBoxItem.ItemsviewSelectedHover.Border" Color="#99006CD9"/>
    <SolidColorBrush x:Key="ComboBoxItem.ItemsviewSelectedNoFocus.Background" Color="#3DDADADA"/>
    <SolidColorBrush x:Key="ComboBoxItem.ItemsviewSelectedNoFocus.Border" Color="#FFDADADA"/>
    <SolidColorBrush x:Key="ComboBoxItem.ItemsviewFocus.Border" Color="#FF26A0DA"/>
    <SolidColorBrush x:Key="ComboBoxItem.ItemsviewHoverFocus.Background" Color="#5426A0DA"/>
    <SolidColorBrush x:Key="ComboBoxItem.ItemsviewHoverFocus.Border" Color="#FF26A0DA"/>
    

    The sort of normal, mouse not focused on and keyboard not focused on, but item is selected, color is the ComboBoxItem.ItemsviewSelectedNoFocus.Background color.

    1 person found this answer helpful.