需求是：仅想改变combobox的默认样式，所以 template 是直接在属性窗口点击转化为本地值的。
using System.Collections.Generic;
using System.Windows;
namespace WpfApp2 {
public partial class MainWindow : Window {
public MainWindow() {
InitializeComponent();
var list = new List<MyClass> { new MyClass { Name = "lwieru" } };
a.ItemsSource = aa.ItemsSource = list;
a.SelectedItem = aa.SelectedItem = list[0];
}
class MyClass {
public string Name { get; set; }
}
}
}
<Window
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:Themes="clr-namespace:Microsoft.Windows.Themes;assembly=PresentationFramework.Aero2"
x:Class="WpfApp2.MainWindow">
<StackPanel>
<ComboBox x:Name="a" DisplayMemberPath="Name"/>
<ComboBox x:Name="aa" DisplayMemberPath="Name">
<ComboBox.Template>
<ControlTemplate 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">
<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}}">
<ToggleButton.Style>
<Style 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="#FFACACAC" BorderThickness="{TemplateBinding BorderThickness}" SnapsToDevicePixels="True">
<Border.Background>
<LinearGradientBrush EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFF0F0F0" Offset="0"/>
<GradientStop Color="#FFE5E5E5" Offset="1"/>
</LinearGradientBrush>
</Border.Background>
<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="F1M0,0L2.667,2.66665 5.3334,0 5.3334,-1.78168 2.6667,0.88501 0,-1.78168 0,0z" Fill="#FF606060" HorizontalAlignment="Center" Margin="0" VerticalAlignment="Center"/>
</Border>
</Border>
<ControlTemplate.Triggers>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, 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="White"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="#FFABADB3"/>
<Setter Property="Background" TargetName="splitBorder" Value="Transparent"/>
<Setter Property="BorderBrush" TargetName="splitBorder" Value="Transparent"/>
</MultiDataTrigger>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Fill" TargetName="Arrow" Value="Black"/>
</Trigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="true"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ComboBox}}}" Value="false"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot">
<Setter.Value>
<LinearGradientBrush EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFECF4FC" Offset="0"/>
<GradientStop Color="#FFDCECFC" Offset="1"/>
</LinearGradientBrush>
</Setter.Value>
</Setter>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="#FF7EB4EA"/>
</MultiDataTrigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsMouseOver, RelativeSource={RelativeSource Self}}" Value="true"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ComboBox}}}" Value="true"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="White"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="#FF7EB4EA"/>
<Setter Property="Background" TargetName="splitBorder">
<Setter.Value>
<LinearGradientBrush EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFEBF4FC" Offset="0"/>
<GradientStop Color="#FFDCECFC" Offset="1"/>
</LinearGradientBrush>
</Setter.Value>
</Setter>
<Setter Property="BorderBrush" TargetName="splitBorder" Value="#FF7EB4EA"/>
</MultiDataTrigger>
<Trigger Property="IsPressed" Value="True">
<Setter Property="Fill" TargetName="Arrow" Value="Black"/>
</Trigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="true"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ComboBox}}}" Value="false"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot">
<Setter.Value>
<LinearGradientBrush EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFDAECFC" Offset="0"/>
<GradientStop Color="#FFC4E0FC" Offset="1"/>
</LinearGradientBrush>
</Setter.Value>
</Setter>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="#FF569DE5"/>
</MultiDataTrigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsPressed, RelativeSource={RelativeSource Self}}" Value="true"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ComboBox}}}" Value="true"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="White"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="#FF569DE5"/>
<Setter Property="Background" TargetName="splitBorder">
<Setter.Value>
<LinearGradientBrush EndPoint="0,1" StartPoint="0,0">
<GradientStop Color="#FFDAEBFC" Offset="0"/>
<GradientStop Color="#FFC4E0FC" Offset="1"/>
</LinearGradientBrush>
</Setter.Value>
</Setter>
<Setter Property="BorderBrush" TargetName="splitBorder" Value="#FF569DE5"/>
</MultiDataTrigger>
<Trigger Property="IsEnabled" Value="False">
<Setter Property="Fill" TargetName="Arrow" Value="#FFBFBFBF"/>
</Trigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="false"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ComboBox}}}" Value="false"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="#FFF0F0F0"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="#FFD9D9D9"/>
</MultiDataTrigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsEnabled, RelativeSource={RelativeSource Self}}" Value="false"/>
<Condition Binding="{Binding IsEditable, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ComboBox}}}" Value="true"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" TargetName="templateRoot" Value="White"/>
<Setter Property="BorderBrush" TargetName="templateRoot" Value="#FFBFBFBF"/>
<Setter Property="Background" TargetName="splitBorder" Value="Transparent"/>
<Setter Property="BorderBrush" TargetName="splitBorder" Value="Transparent"/>
</MultiDataTrigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ToggleButton.Style>
</ToggleButton>
<ContentPresenter x:Name="contentPresenter" ContentTemplate="{TemplateBinding SelectionBoxItemTemplate}" 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="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>
</ComboBox.Template>
</ComboBox>
</StackPanel>
</Window>
来源：https://www.cnblogs.com/ly45/p/12365387.html