WPF - styling comboboxes - wpf

Question

I'm trying to style Comboboxes in WPF so that they are white, and have the same border as TextBoxes. I have the following style so far, but don't know how to set the border:
<Style TargetType="ComboBox">
<Setter Property="Margin" Value="0,2,0,2" />
<Setter Property="VerticalAlignment" Value="Center" />
<Setter Property="Background" Value="White" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ComboBox}">
???
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>

Answer 1

Use Expression Blend. If you want ComboBox to look similar to TextBox, have a look at TextBox template by right clicking TextBlock and selecting Edit Template > Edit a Copy and use that to modify your ComboBox template!

Answer 2

In between your controltemplate please implement something like this:
<Grid SnapsToDevicePixels="true">
<Border
x:Name="Bd"
Background="Transparent"
BorderBrush="#FF888888"
Padding="1"
CornerRadius="5" BorderThickness="2,2,2,2">
<Grid
Grid.IsSharedSizeScope="true">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="1" />
<ColumnDefinition Width="*" />
<ColumnDefinition Width="Auto"
SharedSizeGroup="ComboBoxButton" />
</Grid.ColumnDefinitions>
<Border x:Name="SelectedItemBorder" Grid.ColumnSpan="2" />
<ContentPresenter
SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"
Grid.Column="1"
Content="{TemplateBinding SelectionBoxItem}"
ContentTemplate="{TemplateBinding SelectionBoxItemTemplate}"
ContentTemplateSelector="{TemplateBinding ItemTemplateSelector}"
TextBlock.Foreground="White"
Height="Auto"
Margin="2,2,7,2"
VerticalAlignment="Center" />
<ToggleButton
Style="{StaticResource ComboBoxTransparentButtonStyle}"
Grid.ColumnSpan="3"
IsChecked="{Binding Path=IsDropDownOpen, Mode=TwoWay,
RelativeSource={RelativeSource TemplatedParent}}"
Opacity="0.25" />
</Grid>
</Border>
<Popup Focusable="false" AllowsTransparency="true"
IsOpen="{Binding Path=IsDropDownOpen,
RelativeSource={RelativeSource TemplatedParent}}"
Placement="Bottom"
PopupAnimation="{DynamicResource
{x:Static SystemParameters.ComboBoxPopupAnimationKey}}"
x:Name="PART_Popup">
<Border CornerRadius="5" x:Name="DropDownBorder"
MaxHeight="{TemplateBinding MaxDropDownHeight}"
MinWidth="{TemplateBinding ActualWidth}"
Background="#FF7E7E7E"
BorderThickness="1">
<ScrollViewer Foreground="#FFFFFFFF">
<ItemsPresenter
SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"
KeyboardNavigation.DirectionalNavigation="Contained"
TextBlock.Foreground="White"
VerticalAlignment="Stretch" />
</ScrollViewer>
</Border>
</Popup>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="IsFocused" Value="True">
<Setter Property="BorderBrush" TargetName="Bd" Value="#FFFFFFFF"/>
</Trigger>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="BorderBrush" TargetName="Bd" Value="#FFD2ECCF"/>
</Trigger>
<MultiTrigger>
<MultiTrigger.Conditions>
<Condition Property="IsSelectionBoxHighlighted" Value="true" />
<Condition Property="IsDropDownOpen" Value="false" />
</MultiTrigger.Conditions>
<Setter Property="Foreground" Value="white" />
<Setter Property="BorderBrush" Value="{x:Null}" />
</MultiTrigger>
<Trigger Property="IsSelectionBoxHighlighted" Value="true">
<Setter Property="Background" TargetName="SelectedItemBorder"
Value="Transparent" />
</Trigger>
<Trigger Property="HasDropShadow" SourceName="PART_Popup" Value="true">
</Trigger>
<Trigger Property="HasItems" Value="false">
<Setter Property="MinHeight" TargetName="DropDownBorder" Value="95" />
</Trigger>
<Trigger Property="IsEnabled" Value="false">
<Setter Property="Foreground"
Value="{DynamicResource
{x:Static SystemColors.GrayTextBrushKey}}" />
<Setter Property="Background" TargetName="Bd"
Value="{DynamicResource {x:Static SystemColors.ControlBrushKey}}" />
</Trigger>
<Trigger Property="IsGrouping" Value="true">
<Setter Property="ScrollViewer.CanContentScroll" Value="false" />
</Trigger>
</ControlTemplate.Triggers>