WPF --TextBox--圆角、水印、带单位

  <SolidColorBrush x:Key="TextBox.Static.Border" Color="#FFABAdB3"/>
    <SolidColorBrush x:Key="TextBox.MouseOver.Border" Color="#FF7EB4EA"/>
    <SolidColorBrush x:Key="TextBox.Focus.Border" Color="#FF569DE5"/>
    <VisualBrush x:Key="HintText" TileMode="None" Opacity="0.5" Stretch="None" AlignmentX="Left">
        <VisualBrush.Visual>
            <TextBlock FontStyle="Italic" Text="请输入数据"/>
        </VisualBrush.Visual>
    </VisualBrush>

    <Style x:Key="TBoxLightWatermarkWithUnit" TargetType="{x:Type TextBox}">
        <Setter Property="Background" Value="{DynamicResource {x:Static SystemColors.WindowBrushKey}}"/>
        <Setter Property="BorderBrush" Value="{StaticResource TextBox.Static.Border}"/>
        <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
        <Setter Property="BorderThickness" Value="1"/>
        <Setter Property="KeyboardNavigation.TabNavigation" Value="None"/>
        <Setter Property="HorizontalContentAlignment" Value="Left"/>
        <Setter Property="FocusVisualStyle" Value="{x:Null}"/>
        <Setter Property="AllowDrop" Value="true"/>
        <Setter Property="ScrollViewer.PanningMode" Value="VerticalFirst"/>
        <Setter Property="Stylus.IsFlicksEnabled" Value="False"/>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type TextBox}">
                    <Border x:Name="border" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" SnapsToDevicePixels="True"
                                CornerRadius="2"
                                >
                        <Grid>
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition Width="*"/>
                                <ColumnDefinition Width="35"/>
                            </Grid.ColumnDefinitions>

                            <ScrollViewer Grid.Column="0" x:Name="PART_ContentHost" Focusable="false" HorizontalScrollBarVisibility="Hidden" VerticalScrollBarVisibility="Hidden"/>
                            <TextBlock Grid.Column="1" Text="mm" VerticalAlignment="Center" Margin="0,0,5,0"/>
                        </Grid>
                    </Border>
                    <ControlTemplate.Triggers>
                        <Trigger Property="IsEnabled" Value="false">
                            <Setter Property="Opacity" TargetName="border" Value="0.56"/>
                        </Trigger>
                        <Trigger Property="IsMouseOver" Value="true">
                            <Setter Property="BorderBrush" TargetName="border" Value="{StaticResource TextBox.MouseOver.Border}"/>
                        </Trigger>
                        <Trigger Property="IsKeyboardFocused" Value="true">
                            <Setter Property="BorderBrush" TargetName="border" Value="{StaticResource TextBox.Focus.Border}"/>
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
        <Style.Triggers>
            <MultiTrigger>
                <MultiTrigger.Conditions>
                    <Condition Property="IsInactiveSelectionHighlightEnabled" Value="true"/>
                    <Condition Property="IsSelectionActive" Value="false"/>
                </MultiTrigger.Conditions>
                <Setter Property="SelectionBrush" Value="{DynamicResource {x:Static SystemColors.InactiveSelectionHighlightBrushKey}}"/>
            </MultiTrigger>

            <Trigger Property="Text" Value="{x:Null}">
                <Setter Property="Background" Value="{StaticResource HintText}"/>
            </Trigger>
            <Trigger Property="Text" Value="">
                <Setter Property="Background" Value="{StaticResource HintText}"/>
            </Trigger>

        </Style.Triggers>
    </Style>

　　使用：

    <TextBox
                            Name="txtHeight"
                            FontSize="16"
                            Width="274"
                            Height="40"
                            Margin="15,0,0,0"
                            Text="2840"
                            InputMethod.IsInputMethodEnabled="False"
                            PreviewTextInput="TxtHeight_PreviewTextInput"
                            KeyDown="TxtHeight_KeyDown"
                            HorizontalAlignment="Center"
                            VerticalAlignment="Center" 
                            VerticalContentAlignment="Center"
                            Tag="请输入数字"
                            Style="{DynamicResource TBoxLightWatermarkWithUnit}"/>