WPF DataGrid如何为每列添加独立边框，实现适配列宽的效果

预期效果如下：

核心实现逻辑 #

不需要额外用Grid嵌套Border，直接重写DataGridColumnHeader、DataGridCell的默认样式，给每列的表头和所有单元格套上统一的边框，边框尺寸会自动跟随列宽变化，无需额外维护外部Grid的列参数。

完整修改代码 #

<Window x:Class="WpfApp3.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfApp3"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Grid Background="LightGray">
        <DataGrid ItemsSource="{Binding Items}" 
                  ColumnWidth="*" 
                  AutoGenerateColumns="True" 
                  GridLinesVisibility="None" 
                  Background="Transparent"
                  Margin="5">
            <DataGrid.Resources>
                <!-- 行基础样式 -->
                <Style TargetType="{x:Type DataGridRow}">
                    <Setter Property="Background" Value="Transparent"/>
                </Style>

                <!-- 列头样式：带顶部圆角边框 -->
                <Style TargetType="{x:Type DataGridColumnHeader}">
                    <Setter Property="Background" Value="Transparent"/>
                    <Setter Property="BorderThickness" Value="0"/>
                    <Setter Property="Padding" Value="10,5"/>
                    <Setter Property="Template">
                        <Setter.Value>
                            <ControlTemplate TargetType="DataGridColumnHeader">
                                <Border CornerRadius="5 5 0 0" 
                                        BorderThickness="1 1 1 0" 
                                        BorderBrush="Black" 
                                        Background="White"
                                        Margin="0 0 10 0">
                                    <ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"/>
                                </Border>
                            </ControlTemplate>
                        </Setter.Value>
                    </Setter>
                </Style>

                <!-- 普通单元格样式：带左右边框 -->
                <Style TargetType="{x:Type DataGridCell}">
                    <Setter Property="BorderThickness" Value="0"/>
                    <Setter Property="Padding" Value="10,5"/>
                    <Setter Property="Template">
                        <Setter.Value>
                            <ControlTemplate TargetType="DataGridCell">
                                <Border BorderThickness="1 0 1 0" 
                                        BorderBrush="Black" 
                                        Background="White"
                                        Margin="0 0 10 0">
                                    <ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"/>
                                </Border>
                            </ControlTemplate>
                        </Setter.Value>
                    </Setter>
                </Style>

                <!-- 最后一行单元格样式：额外加底部圆角 -->
                <Style TargetType="{x:Type DataGridRow}">
                    <Style.Triggers>
                        <Trigger Property="IsLastItemInContainer" Value="True">
                            <Setter Property="CellStyle">
                                <Setter.Value>
                                    <Style TargetType="DataGridCell" BasedOn="{StaticResource {x:Type DataGridCell}}">
                                        <Setter Property="Template">
                                            <Setter.Value>
                                                <ControlTemplate TargetType="DataGridCell">
                                                    <Border CornerRadius="0 0 5 5" 
                                                            BorderThickness="1 0 1 1" 
                                                            BorderBrush="Black" 
                                                            Background="White"
                                                            Margin="0 0 10 0">
                                                        <ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"/>
                                                    </Border>
                                                </ControlTemplate>
                                            </Setter.Value>
                                        </Setter>
                                    </Style>
                                </Setter.Value>
                            </Setter>
                        </Trigger>
                    </Style.Triggers>
                </Style>
            </DataGrid.Resources>
        </DataGrid>
    </Grid>
</Window>

效果说明 #

• 边框完全依附于列元素，列宽调整、列数量增减时边框会自动同步，不会出现错位
• 列间距、圆角大小、边框颜色等参数可以直接修改样式中的Margin、CornerRadius、BorderBrush属性自定义
• 支持自动生成列和手动定义列两种使用场景，无需额外适配

内容的提问来源于stack exchange，提问作者mister_giga