How to create ComboBox background for mouse?

Question

I have a rounded border containing a ComboBox

<Border CornerRadius="10" BorderBrush...> <ComboBox Background="{x:Null}"> <ComboBoxItem ...> <ComboBoxItem ...> </ComboBox> </Border> 

When my mouse does not hover over the Combobox, it looks beautiful and transparent. Like this:

When the mouse hovers over it, it then creates an old Button-like background, for example:

I would like the ComboBox to have a transparent background even when the mouse is on top. I tried various ways, including writing MouseEnter, MouseLeave, MouseMove, to set the background to zero, but without success.

 private void ComboBox_MouseEnter(object sender, RoutedEventArgs e) { comboBox1.Background = null; } 

Then I try to install styling:

 <Window.Resources> <Style TargetType="{x:Type ComboBox}" x:Key="HoverBox"> <Style.Triggers> <Trigger Property="IsMouseOver" Value="True"> <Setter Property="Background" Value="Pink" /> </Trigger> </Style.Triggers> </Style> </Window.Resources> 

that didn't work either. Then I tried to change the control pattern:

 <ControlTemplate TargetType="{x:Type ComboBox}" x:Key="MouseHover"> <ControlTemplate.Triggers> <Trigger Property="IsMouseOver" Value="True"> <Setter Property="Background" Value="Red" /> <Setter Property="Foreground" Value="Green" /> </Trigger> </ControlTemplate.Triggers> </ControlTemplate> 

Worse, after changing the control template, the ComboBox disappears, for example:

I did my best, but I still get this ugly button on my ComboBox whenever my mouse hovers over it.

Does anyone know what's wrong here?

Answer 1

Check your previous posts asking for the same

Unable to style WPF ComboBox on hover

How to change the background property of a ComboBox while mouse

EDIT

Use this. The following is the default checklist for combobox. Pay attention to the commented line of code for your requirement

  <Window.Resources> <!-- Fill Brushes --> <LinearGradientBrush x:Key="NormalBrush" StartPoint="0,0" EndPoint="0,1"> <GradientBrush.GradientStops> <GradientStopCollection> <GradientStop Color="#FFF" Offset="0.0"/> <GradientStop Color="#CCC" Offset="1.0"/> </GradientStopCollection> </GradientBrush.GradientStops> </LinearGradientBrush> <LinearGradientBrush x:Key="HorizontalNormalBrush" StartPoint="0,0" EndPoint="1,0"> <GradientBrush.GradientStops> <GradientStopCollection> <GradientStop Color="#FFF" Offset="0.0"/> <GradientStop Color="#CCC" Offset="1.0"/> </GradientStopCollection> </GradientBrush.GradientStops> </LinearGradientBrush> <LinearGradientBrush x:Key="LightBrush" StartPoint="0,0" EndPoint="0,1"> <GradientBrush.GradientStops> <GradientStopCollection> <GradientStop Color="#FFF" Offset="0.0"/> <GradientStop Color="#EEE" Offset="1.0"/> </GradientStopCollection> </GradientBrush.GradientStops> </LinearGradientBrush> <LinearGradientBrush x:Key="HorizontalLightBrush" StartPoint="0,0" EndPoint="1,0"> <GradientBrush.GradientStops> <GradientStopCollection> <GradientStop Color="#FFF" Offset="0.0"/> <GradientStop Color="#EEE" Offset="1.0"/> </GradientStopCollection> </GradientBrush.GradientStops> </LinearGradientBrush> <LinearGradientBrush x:Key="DarkBrush" StartPoint="0,0" EndPoint="0,1"> <GradientBrush.GradientStops> <GradientStopCollection> <GradientStop Color="#FFF" Offset="0.0"/> <GradientStop Color="#AAA" Offset="1.0"/> </GradientStopCollection> </GradientBrush.GradientStops> </LinearGradientBrush> <LinearGradientBrush x:Key="PressedBrush" StartPoint="0,0" EndPoint="0,1"> <GradientBrush.GradientStops> <GradientStopCollection> <GradientStop Color="#BBB" Offset="0.0"/> <GradientStop Color="#EEE" Offset="0.1"/> <GradientStop Color="#EEE" Offset="0.9"/> <GradientStop Color="#FFF" Offset="1.0"/> </GradientStopCollection> </GradientBrush.GradientStops> </LinearGradientBrush> <SolidColorBrush x:Key="DisabledForegroundBrush" Color="#888" /> <SolidColorBrush x:Key="DisabledBackgroundBrush" Color="#EEE" /> <SolidColorBrush x:Key="WindowBackgroundBrush" Color="#FFF" /> <SolidColorBrush x:Key="SelectedBackgroundBrush" Color="#DDD" /> <!-- Border Brushes --> <LinearGradientBrush x:Key="NormalBorderBrush" StartPoint="0,0" EndPoint="0,1"> <GradientBrush.GradientStops> <GradientStopCollection> <GradientStop Color="#CCC" Offset="0.0"/> <GradientStop Color="#444" Offset="1.0"/> </GradientStopCollection> </GradientBrush.GradientStops> </LinearGradientBrush> <LinearGradientBrush x:Key="HorizontalNormalBorderBrush" StartPoint="0,0" EndPoint="1,0"> <GradientBrush.GradientStops> <GradientStopCollection> <GradientStop Color="#CCC" Offset="0.0"/> <GradientStop Color="#444" Offset="1.0"/> </GradientStopCollection> </GradientBrush.GradientStops> </LinearGradientBrush> <LinearGradientBrush x:Key="DefaultedBorderBrush" StartPoint="0,0" EndPoint="0,1"> <GradientBrush.GradientStops> <GradientStopCollection> <GradientStop Color="#777" Offset="0.0"/> <GradientStop Color="#000" Offset="1.0"/> </GradientStopCollection> </GradientBrush.GradientStops> </LinearGradientBrush> <LinearGradientBrush x:Key="PressedBorderBrush" StartPoint="0,0" EndPoint="0,1"> <GradientBrush.GradientStops> <GradientStopCollection> <GradientStop Color="#444" Offset="0.0"/> <GradientStop Color="#888" Offset="1.0"/> </GradientStopCollection> </GradientBrush.GradientStops> </LinearGradientBrush> <SolidColorBrush x:Key="DisabledBorderBrush" Color="#AAA" /> <SolidColorBrush x:Key="SolidBorderBrush" Color="#888" /> <SolidColorBrush x:Key="LightBorderBrush" Color="#AAA" /> <!-- Miscellaneous Brushes --> <SolidColorBrush x:Key="GlyphBrush" Color="#444" /> <SolidColorBrush x:Key="LightColorBrush" Color="#DDD" /> <ControlTemplate x:Key="ComboBoxToggleButton" TargetType="ToggleButton"> <Grid> <Grid.ColumnDefinitions> <ColumnDefinition /> <ColumnDefinition Width="20" /> </Grid.ColumnDefinitions> <Border x:Name="Border" Grid.ColumnSpan="2" CornerRadius="2" Background="{StaticResource NormalBrush}" BorderBrush="{StaticResource NormalBorderBrush}" BorderThickness="1" /> <Border Grid.Column="0" CornerRadius="2,0,0,2" Margin="1" Background="{StaticResource WindowBackgroundBrush}" BorderBrush="{StaticResource NormalBorderBrush}" BorderThickness="0,0,1,0" /> <Path x:Name="Arrow" Grid.Column="1" Fill="{StaticResource GlyphBrush}" HorizontalAlignment="Center" VerticalAlignment="Center" Data="M 0 0 L 4 4 L 8 0 Z"/> </Grid> <ControlTemplate.Triggers> <!--<Trigger Property="ToggleButton.IsMouseOver" Value="true"> <Setter TargetName="Border" Property="Background" Value="{StaticResource DarkBrush}" /> </Trigger>--> <Trigger Property="ToggleButton.IsChecked" Value="true"> <Setter TargetName="Border" Property="Background" Value="{StaticResource PressedBrush}" /> </Trigger> <Trigger Property="IsEnabled" Value="False"> <Setter TargetName="Border" Property="Background" Value="{StaticResource DisabledBackgroundBrush}" /> <Setter TargetName="Border" Property="BorderBrush" Value="{StaticResource DisabledBorderBrush}" /> <Setter Property="Foreground" Value="{StaticResource DisabledForegroundBrush}"/> <Setter TargetName="Arrow" Property="Fill" Value="{StaticResource DisabledForegroundBrush}" /> </Trigger> </ControlTemplate.Triggers> </ControlTemplate> <ControlTemplate x:Key="ComboBoxTextBox" TargetType="TextBox"> <Border x:Name="PART_ContentHost" Focusable="False" Background="{TemplateBinding Background}" /> </ControlTemplate> <Style x:Key="{x:Type ComboBox}" TargetType="ComboBox"> <Setter Property="SnapsToDevicePixels" Value="true"/> <Setter Property="OverridesDefaultStyle" Value="true"/> <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Auto"/> <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto"/> <Setter Property="ScrollViewer.CanContentScroll" Value="true"/> <Setter Property="MinWidth" Value="120"/> <Setter Property="MinHeight" Value="20"/> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="ComboBox"> <Grid> <ToggleButton Name="ToggleButton" Template="{StaticResource ComboBoxToggleButton}" Grid.Column="2" Focusable="false" IsChecked="{Binding Path=IsDropDownOpen,Mode=TwoWay,RelativeSource={RelativeSource TemplatedParent}}" ClickMode="Press"> </ToggleButton> <ContentPresenter Name="ContentSite" IsHitTestVisible="False" Content="{TemplateBinding SelectionBoxItem}" ContentTemplate="{TemplateBinding SelectionBoxItemTemplate}" ContentTemplateSelector="{TemplateBinding ItemTemplateSelector}" Margin="3,3,23,3" VerticalAlignment="Center" HorizontalAlignment="Left" /> <TextBox x:Name="PART_EditableTextBox" Style="{x:Null}" Template="{StaticResource ComboBoxTextBox}" HorizontalAlignment="Left" VerticalAlignment="Center" Margin="3,3,23,3" Focusable="True" Background="Transparent" Visibility="Hidden" IsReadOnly="{TemplateBinding IsReadOnly}"/> <Popup Name="Popup" Placement="Bottom" IsOpen="{TemplateBinding IsDropDownOpen}" AllowsTransparency="True" Focusable="False" PopupAnimation="Slide"> <Grid Name="DropDown" SnapsToDevicePixels="True" MinWidth="{TemplateBinding ActualWidth}" MaxHeight="{TemplateBinding MaxDropDownHeight}"> <Border x:Name="DropDownBorder" Background="{StaticResource WindowBackgroundBrush}" BorderThickness="1" BorderBrush="{StaticResource SolidBorderBrush}"/> <ScrollViewer Margin="4,6,4,6" SnapsToDevicePixels="True"> <StackPanel IsItemsHost="True" KeyboardNavigation.DirectionalNavigation="Contained" /> </ScrollViewer> </Grid> </Popup> </Grid> <ControlTemplate.Triggers> <Trigger Property="HasItems" Value="false"> <Setter TargetName="DropDownBorder" Property="MinHeight" Value="95"/> </Trigger> <Trigger Property="IsEnabled" Value="false"> <Setter Property="Foreground" Value="{StaticResource DisabledForegroundBrush}"/> </Trigger> <Trigger Property="IsGrouping" Value="true"> <Setter Property="ScrollViewer.CanContentScroll" Value="false"/> </Trigger> <Trigger SourceName="Popup" Property="Popup.AllowsTransparency" Value="true"> <Setter TargetName="DropDownBorder" Property="CornerRadius" Value="4"/> <Setter TargetName="DropDownBorder" Property="Margin" Value="0,2,0,0"/> </Trigger> <Trigger Property="IsEditable" Value="true"> <Setter Property="IsTabStop" Value="false"/> <Setter TargetName="PART_EditableTextBox" Property="Visibility" Value="Visible"/> <Setter TargetName="ContentSite" Property="Visibility" Value="Hidden"/> </Trigger> </ControlTemplate.Triggers> </ControlTemplate> </Setter.Value> </Setter> <Style.Triggers> </Style.Triggers> </Style> </Window.Resources>