自定义ComboBox控件

建一个ResourceDictionary样式xaml：

<!--ComboBox样式自定义-->
    <!--ComBoBox项选中背景色-->
    <SolidColorBrush x:Key="ComboBoxSelectdBackground"
                     Color="#E3E6ED" />
    <!--ComBoBox项鼠标经过背景色-->
    <SolidColorBrush x:Key="ComboBoxMouseOverBackground"
                     Color="#E3E6ED" />
    <!--ComBoBox项选中前景色-->
    <SolidColorBrush x:Key="ComboBoxSelectedForeground"
                     Color="#333333" />
    <!--ComBoBox项鼠标经过前景色-->
    <SolidColorBrush x:Key="ComboBoxMouseOverForegrond"
                     Color="#333333" />

    <!--ComboBox右侧的三角按钮-->
    <ControlTemplate x:Key="ComboBoxToggleButton"
                     TargetType="{x:Type ToggleButton}">
        <Grid Height="25"
              HorizontalAlignment="Stretch">
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="*" />
                <ColumnDefinition Width="30" />
            </Grid.ColumnDefinitions>
            <Border  Background="White"
                     Grid.ColumnSpan="2"
                     Opacity="0" />
            <Path x:Name="Arrow"
                  Grid.Column="1"
                  Data="M 0 0  6 6 12 0 Z"
                  VerticalAlignment="Center"
                  HorizontalAlignment="Center"
                  Stretch="None"
                  Fill="#999" />
        </Grid>

        <ControlTemplate.Triggers>
            <Trigger Property="IsChecked"
                     Value="true">
                <Setter TargetName="Arrow"
                        Property="RenderTransform">
                    <Setter.Value>
                        <RotateTransform   CenterX="6"
                                           CenterY="3"
                                           Angle="180"></RotateTransform>
                    </Setter.Value>
                </Setter>
                <Setter TargetName="Arrow"
                        Property="Margin"
                        Value="0 0 0 2" />
            </Trigger>
        </ControlTemplate.Triggers>
    </ControlTemplate>

    <!--ComboBox-->
    <Style TargetType="{x:Type ComboBox}"
           x:Key="ComboBoxStyle">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type ComboBox}">
                    <Grid Name="grid">
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition Width="0.7*" />
                            <ColumnDefinition Width="0.3*"
                                              MaxWidth="30" />
                        </Grid.ColumnDefinitions>
                        <Border  Grid.Column="0"
                                 Grid.ColumnSpan="2"
                                 BorderThickness="1"
                                 BorderBrush="#dddddd"
                                 CornerRadius="3,3,3,3">
                        </Border>
                        <ContentPresenter HorizontalAlignment="Left"
                                          Margin="3,3,0,3"
                                          x:Name="ContentSite"
                                          VerticalAlignment="Center"
                                          Content="{TemplateBinding SelectionBoxItem}"
                                          ContentTemplate="{TemplateBinding SelectionBoxItemTemplate}"
                                          ContentTemplateSelector="{TemplateBinding ItemTemplateSelector}"
                                          IsHitTestVisible="False" />

                        <!--ToggleButton 已数据绑定到 ComboBox 本身以切换 IsDropDownOpen-->
                        <ToggleButton Grid.Column="0"
                                      Grid.ColumnSpan="2"
                                      Template="{StaticResource ComboBoxToggleButton}"
                                      x:Name="ToggleButton"
                                      Focusable="false"
                                      IsChecked="{Binding Path=IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}"
                                      ClickMode="Press" />
                        <!--必须将 TextBox 命名为 PART_EditableTextBox，否则 ComboBox 将无法识别它-->
                        <TextBox   Visibility="Hidden"
                                   BorderThickness="0"
                                   Margin="2 0 0 0"
                                   x:Name="PART_EditableTextBox"
                                   VerticalAlignment="Center"
                                   Focusable="True"
                                   IsReadOnly="{TemplateBinding IsReadOnly}" />

                        <!--Popup 可显示 ComboBox 中的项列表。IsOpen 已数据绑定到通过 ComboBoxToggleButton 来切换的 IsDropDownOpen-->
                        <Popup IsOpen="{TemplateBinding IsDropDownOpen}"
                               Placement="Bottom"
                               x:Name="Popup"
                               Focusable="False"
                               AllowsTransparency="True"
                               PopupAnimation="Slide">
                            <Grid MaxHeight="350"
                                  MinWidth="{TemplateBinding ActualWidth}"
                                  x:Name="DropDown"
                                  SnapsToDevicePixels="True">
                                <Border x:Name="DropDownBorder"
                                        BorderBrush="#e8e8e8"
                                        BorderThickness="1 0 1 1"
                                        CornerRadius="3,3,3,3" />
                                <ScrollViewer Margin="1"
                                              SnapsToDevicePixels="True"
                                              HorizontalScrollBarVisibility="Auto"
                                              VerticalScrollBarVisibility="Auto"
                                              CanContentScroll="True">
                                    <!--StackPanel 用于显示子级，方法是将 IsItemsHost 设置为 True-->
                                    <StackPanel IsItemsHost="True"
                                                KeyboardNavigation.DirectionalNavigation="Contained"
                                                Background="White" />
                                </ScrollViewer>
                            </Grid>
                        </Popup>
                    </Grid>
                    <ControlTemplate.Triggers>
                        <Trigger Property="IsEditable"
                                 Value="true">
                            <Setter TargetName="PART_EditableTextBox"
                                    Property="Visibility"
                                    Value="Visible" />
                        </Trigger>
                        <Trigger Property="IsEnabled"
                                 Value="False">
                            <Setter TargetName="grid"
                                    Property="Background"
                                    Value="#F2F3F5">
                            </Setter>
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
       
    </Style>

新建一个类

   public class TzxComboBox: System.Windows.Controls.ComboBox
    {
        public TzxComboBox()
        {
            Style style = this.TryFindResource("ComboBoxStyle") as Style;
            if (style != null)
            {
                this.Style = style;
            }
        }
    }

在xaml页面引用comboBox控件：

xmlns:ComboBox="clr-namespace:TzxControlComponentLib.Controls.ComboBoxs;assembly=TzxControlComponentLib"

使用并绑定一个集合list：

<ComboBox:TzxComboBox x:Name="ComboBoxDepartment"
                                      ItemsSource="{Binding List}"
                                      SelectedValuePath="pk"
                                      DisplayMemberPath="v_name"
                                      HorizontalAlignment="Left"
                                      Margin="120,0,16,0"
                                      VerticalAlignment="Center"
                                      Width="128"
                                      Height="35"
                                      FontSize="16"/>