ScrollToVerticalOffset()不起作用?

时间:2013-07-26 03:19:42

标签: c# wpf

我在WPF中使用ScrollView,我的应用程序允许用户点击按钮,然后它会自动滚动滚动视图,我在按钮点击事件中使用ScrollToVerticalOffset(),但是滚动视图没有改变任何东西。

我在互联网上搜索过这个问题,但到目前为止我还不能解决它。

还有一个问题:ScrollToVerticalOffset()采用double作为参数,它可能会滚动到特殊像素,有没有办法滚动到n项(不是像素)?

这是我的代码

<ScrollViewer x:Name="scrollViewerChannelBtns" Grid.Row="1" HorizontalAlignment="Left" VerticalAlignment="Center" 
              Background="Transparent" VerticalScrollBarVisibility="Hidden" HorizontalScrollBarVisibility="Hidden"
              CanContentScroll="True" ScrollChanged="ScrollViewerChannelBtns_ScrollChanged">
    <StackPanel x:Name="channelBtns" Orientation="Vertical">
        <ItemsControl x:Name="channelBtnItems" ItemsSource="{Binding}">
            <ItemsControl.ItemTemplate>
                <DataTemplate>
                    <ToggleButton x:Name="tgbChannelName" Width="{Binding Path=ChannelNameBtnWidth}" Height="{Binding Path=ChannelNameBtnHeight}" HorizontalAlignment="Left" VerticalAlignment="Center" IsChecked="{Binding Path=IsChecked, Mode=TwoWay}" Content="{Binding Path=ChannelName}" Tag="{Binding Path=Index}"/>
                </DataTemplate>
            </ItemsControl.ItemTemplate>
        </ItemsControl>
    </StackPanel>
</ScrollViewer>  

C#代码

//The button click event handled
private void BtnScrollDownClicked(object sender, RoutedEventArgs e)
{                        scrollViewerChannelBtns.ScrollToVerticalOffset(scrollViewerChannelBtns.VerticalOffset + 50);
}
private void BtnScrollUpClicked(object sender, RoutedEventArgs e)
{                        scrollViewerChannelBtns.ScrollToVerticalOffset(scrollViewerChannelBtns.VerticalOffset - 50);
}

非常感谢, T&amp; T公司

2 个答案:

答案 0 :(得分:8)

我的工作开始了;

  ScrollViewer.UpdateLayout();                              
  ScrollViewer.ScrollToVerticalOffset(outPoint.Y);

答案 1 :(得分:2)

对我来说,这个例子有效:

xmlns:sys="clr-namespace:System;assembly=mscorlib"

<Grid>
    <ScrollViewer x:Name="scrollViewerChannelBtns" HorizontalAlignment="Center" Height="100" CanContentScroll="False" VerticalAlignment="Center" 
          Background="Transparent" VerticalScrollBarVisibility="Auto">

        <StackPanel x:Name="channelBtns" Orientation="Vertical">
            <ItemsControl x:Name="channelBtnItems">
                <ItemsControl.ItemTemplate>
                    <DataTemplate>
                        <ToggleButton x:Name="tgbChannelName" Width="40" Height="20" HorizontalAlignment="Left" VerticalAlignment="Center" IsChecked="{x:Null}" Content="Test" />
                    </DataTemplate>
                </ItemsControl.ItemTemplate>

                <sys:String>Item 1</sys:String>
                <sys:String>Item 2</sys:String>
                <sys:String>Item 3</sys:String>
                <sys:String>Item 4</sys:String>
                <sys:String>Item 5</sys:String>
                <sys:String>Item 6</sys:String>
                <sys:String>Item 7</sys:String>
                <sys:String>Item 8</sys:String>
                <sys:String>Item 9</sys:String>
                <sys:String>Item 10</sys:String>
            </ItemsControl>
        </StackPanel>
    </ScrollViewer>

    <Button Name="Up" Width="50" Height="30" VerticalAlignment="Top" Margin="110,0,0,0" Content="Up" Click="Up_Click" />

    <Button Name="Down" Width="50" Height="30" VerticalAlignment="Top" Margin="210,0,0,0" Content="Down" Click="Down_Click" />
</Grid>

在示例中,我设置了ScrollViewerCanContentScroll设置false的高度。引用回答why setting ScrollViewer.CanContentScroll to false disable virtualization

  

ScrollViewer目前允许两种滚动模式:平滑的逐像素滚动(CanContentScroll = false)或逐项逐项滚动(CanContentScroll = true)。目前,WPF仅在按项目滚动时支持UI虚拟化。基于像素的滚动也称为“物理滚动”,基于项目的滚动也称为“逻辑滚动”。

     

虚拟化需要基于项目的滚动,因此它可以跟踪当前视图中的逻辑单元(项目)...将ScrollViewer设置为基于像素的滚动它们不再是逻辑单元的概念,而只是像素!

Code behind

private void Up_Click(object sender, RoutedEventArgs e)
{
    scrollViewerChannelBtns.ScrollToVerticalOffset(scrollViewerChannelBtns.VerticalOffset - 50);
}

private void Down_Click(object sender, RoutedEventArgs e)
{
    scrollViewerChannelBtns.ScrollToVerticalOffset(scrollViewerChannelBtns.VerticalOffset + 50);
}

默认情况下不支持滚动元素,因此您必须查看以下链接:

Consolidated Scrolling - "Pixel by Pixel" + "Item by Item"

ScrollViewer's Viewport Height VS Actual Height