WPF scrollbar滚动量修改

要修改 WPF ScrollBar 的滚动量，可以使用 ScrollViewer 控件。在 ScrollViewer 中，可以通过修改 VerticalScrollBar 或 HorizontalScrollBar 的 SmallChange 或 LargeChange 属性来修改滚动量。

例如，如果要将 ScrollBar 的滚动量从默认的 16 修改为 20，可以在 XAML 中添加以下代码：

<ScrollViewer>
    <ScrollViewer.Resources>
        <!-- 获取垂直 ScrollBar -->
        <Style TargetType="ScrollBar">
            <Setter Property="OverridesDefaultStyle" Value="True"/>
            <Setter Property="Width" Value="18"/>
            <Setter Property="Minimum" Value="0"/>
            <Setter Property="Maximum" Value="100"/>
            <Setter Property="Orientation" Value="Vertical"/>
            <Setter Property="Foreground" Value="White"/>
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="ScrollBar">
                        <Grid x:Name="GridRoot" Width="18" Background="{StaticResource DarkBrush}">
                            <Grid.RowDefinitions>
                                <RowDefinition MaxHeight="18"/>
                                <RowDefinition Height="0.00001*"/>
                                <RowDefinition MaxHeight="18"/>
                            </Grid.RowDefinitions>
                            <RepeatButton x:Name="LineUpButton" Command="ScrollBar.LineUpCommand" Background="{StaticResource DarkBrush}" Content="M 0 4 L 8 4 L 4 0 Z" Height="18" Visibility="Collapsed"/>
                            <Track x:Name="PART_Track" Grid.Row="1" IsDirectionReversed="true">
                                <Track.DecreaseRepeatButton>
                                    <RepeatButton Command="ScrollBar.PageUpCommand" Background="{StaticResource DarkBrush}"/>
                                </Track.DecreaseRepeatButton>
                                <Track.Thumb>
                                    <Thumb x:Name="Thumb" Background="{StaticResource LightBrush}" BorderBrush="{StaticResource DarkBrush}" BorderThickness="1" Width="12"/>
                                </Track.Thumb>
                                <Track.IncreaseRepeatButton>
                                    <RepeatButton Command="ScrollBar.PageDownCommand" Background="{StaticResource DarkBrush}"/>
                                </Track.IncreaseRepeatButton>
                            </Track>
                            <RepeatButton x:Name="LineDownButton" Grid.Row="2" Command="ScrollBar.LineDownCommand" Background="{StaticResource DarkBrush}" Content="M 0 0 L 4 4 L 8 0 Z" Height="18" Visibility="Collapsed"/>
                        </Grid>
                        <ControlTemplate.Triggers>
                            <Trigger Property="IsEnabled" Value="False">
                                <Setter TargetName="Thumb" Property="Visibility" Value="Collapsed"/>
                            </Trigger>
                            <Trigger Property="Orientation" Value="Horizontal">
                                <Setter TargetName="GridRoot" Property="LayoutTransform">
                                    <Setter.Value>
                                        <RotateTransform Angle="-90"/>
                                    </Setter.Value>
                                </Setter>
                                <Setter TargetName="PART_Track" Property="LayoutTransform">
                                    <Setter.Value>
                                        <RotateTransform Angle="-90"/>
                                    </Setter.Value>
                                </Setter>
                                <Setter Property="Width" Value="Auto"/>
                                <Setter Property="Height" Value="18"/>
                                <Setter TargetName="LineUpButton" Property="LayoutTransform">
                                    <Setter.Value>
                                        <RotateTransform Angle="90"/>
                                    </Setter.Value>
                                </Setter>
                                <Setter TargetName="LineDownButton" Property="LayoutTransform">
                                    <Setter.Value>
                                        <RotateTransform Angle="90"/>
                                    </Setter.Value>
                                </Setter>
                            </Trigger>
                            <!-- 修改 SmallChange 和 LargeChange -->
                            <Trigger Property="IsMouseOver" Value="True">
                                <Setter Property="Background" TargetName="GridRoot" Value="{StaticResource LightBrush}"/>
                                <Setter Property="Visibility" TargetName="LineUpButton" Value="Visible"/>
                                <Setter Property="Visibility" TargetName="LineDownButton" Value="Visible"/>
                            </Trigger>
                            <Trigger Property="IsDragging" Value="True">
                                <Setter Property="Background" TargetName="GridRoot" Value="{StaticResource LightBrush}"/>
                            </Trigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </ScrollViewer.Resources>

    <!-- 添加内容 -->
    <StackPanel>
        <TextBlock Text="1"/>
        <TextBlock Text="2"/>
        <TextBlock Text="3"/>
        <TextBlock Text="4"/>
        <TextBlock Text="5"/>
        <TextBlock Text="6"/>
        <TextBlock Text="7"/>
        <TextBlock Text="8"/>
        <TextBlock Text="9"/>
        <TextBlock Text="10"/>
        <TextBlock Text="11"/>
        <TextBlock Text="12"/>
        <TextBlock Text="13"/>
        <TextBlock Text="14"/>
        <TextBlock Text="15"/>
        <TextBlock Text="16"/>
        <TextBlock Text="17"/>
        <TextBlock Text="18"/>
        <TextBlock Text="19"/>
        <TextBlock Text="20"/>
    </StackPanel>
</ScrollViewer>

在上面的代码中，我们通过修改 ScrollBar 的 SmallChange 和 LargeChange 属性，将滚动量从默认的 16 修改为 20。

请注意，这里的代码是针对垂直 ScrollBar 的。如果需要修改水平 ScrollBar 的滚动量，可以在上面的代码中，将 Orientation 属性设置为 Horizontal，并将 Width 和 Height 的值交换。