wpf scrollviewer在scrollbar上的事件获取不到

Question

我有一个scrollviewer想获取鼠标或者触笔在它的右侧scrollbar的down、up事件，该如何做。

我使用了style、以及获取内部scrollbar等方法均无法实现。

谢谢

Answer 1

你好，

一般情况下，我们只需要处理ScrollChanged事件即可，在我这边，测试了使用触摸和鼠标下的右侧scrollbar down/up动作，这个事件均可以获取。

我的XAML代码如下：

<Window.Resources>
        <x:Array x:Key="TestArray" Type="{x:Type sys:String}">
            <sys:String>TEST 1</sys:String>
            <sys:String>TEST 2</sys:String>
            <sys:String>TEST 3</sys:String>
            <sys:String>TEST 4</sys:String>
            <sys:String>TEST 5</sys:String>
            <sys:String>TEST 6</sys:String>
            <sys:String>TEST 7</sys:String>
            <sys:String>TEST 8</sys:String>
            <sys:String>TEST 9</sys:String>
            <sys:String>TEST 10</sys:String>
        </x:Array>
    </Window.Resources>
    <Grid>
        <ScrollViewer Height="180" ScrollChanged="ScrollViewer_ScrollChanged">

            <StackPanel>
                <ItemsControl ItemsSource="{StaticResource TestArray}"
                                  FontSize="16" />
            </StackPanel>
        </ScrollViewer>
    </Grid>

如果需要进一步帮助，请提供足够的可还原的代码帮助我们重现问题。

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Answer 2

能贴一下你的获取触摸和鼠标下的右侧scrollbar down/up的实现吗？我对照着看下，谢谢

Answer 3

基于第一条回复中的代码，我添加了一个TextBlock去显示向上/向下，利用ScrollChangedEventArgs的VerticalChange属性，负数表示向上滚动：

private void ScrollViewer_ScrollChanged(object sender, ScrollChangedEventArgs e)
{
            if (e.VerticalChange < 0)
                txb.Text = "Up";
            else
                txb.Text = "Down";
}

截图：

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Answer 4

基于第一条回复中的代码，我添加了一个TextBlock去显示向上/向下，利用ScrollChangedEventArgs的VerticalChange属性，负数表示向上滚动：

private void ScrollViewer_ScrollChanged(object sender, ScrollChangedEventArgs e)
{
            if (e.VerticalChange < 0)
                txb.Text = "Up";
            else
                txb.Text = "Down";
}

截图：

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我没有说全，我说的是在scrollbar上的LeftMouseDown、LeftMouseUp、TouchDown、TouchUp的事件

不是向上、向下滚动

Answer 5

Okay，我们可以在Load事件中定位到ScrollViewer中的ScrollBar，然后添加PreviewMouseDown和 PreviewMouseUp 事件：

private void Window_Loaded(object sender, RoutedEventArgs e)
{
            ScrollBar s = myScrollViewer.Template.FindName("PART_VerticalScrollBar", myScrollViewer) as ScrollBar;
            if (s != null)
            {
                s.PreviewMouseDown += myScrollBar_PreviewMouseDown;
                s.PreviewMouseUp += myScrollBar_PreviewMouseUp;
            }
}

private void myScrollBar_PreviewMouseDown(object sender, MouseButtonEventArgs e)
{
            ;
}

private void myScrollBar_PreviewMouseUp(object sender, MouseButtonEventArgs e)
{
            ;
}

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Answer 6

PreviewMouseDown和 PreviewMouseUp事件可以触发，但是MouseDown和 MouseUp均没有触发，被丢弃了。

如不行，就采用PreviewMouseDown和 PreviewMouseUp吧

谢谢