WPF学习笔记（5）：两个DataGrid的滚动条实现同步滚动

效果：两个DataGrid的滚动条实现同步滚动。

代码参考了博客园chuncn的文章《.net中同步多个ScrollViewer滚动的四种方法》，原文是针对ListBox的。现改为针对DataGrid，略微作了修改，代码以水平滚动条为例。

原文地址：https://www.cnblogs.com/chuncn/archive/2011/10/08/2202175.html

实现方法：

方法一：利用DependencyProperty类的RegisterAttached方法，在属性系统上注册附加属性，并将滚动条属性值HorizontalOffset通过注册属性关联到一个方法。

ScrollViewer sv1, sv2;

private void Window_Loaded(object sender, RoutedEventArgs e)
{
    //分别获取两个DataGrid的ScrollViewer
    sv1 = VisualTreeHelper.GetChild(VisualTreeHelper.GetChild(this.DataGrid1, 0), 0) as ScrollViewer;
    sv2 = VisualTreeHelper.GetChild(VisualTreeHelper.GetChild(this.DataGrid2, 0), 0) as ScrollViewer;

    //将滚动条属性值HorizontalOffset关联到OnScrollChanged1方法
    var offsetChangeListener = DependencyProperty.RegisterAttached("ListenerOffset1", typeof(object), typeof(UserControl), new PropertyMetadata(OnScrollChanged1));
    var binding = new Binding("HorizontalOffset") { Source = sv1 };
    sv1.SetBinding(offsetChangeListener, binding);

    offsetChangeListener = DependencyProperty.RegisterAttached("ListenerOffset2", typeof(object), typeof(UserControl), new PropertyMetadata(OnScrollChanged2));
    binding = new Binding("HorizontalOffset") { Source = sv2 };
    sv2.SetBinding(offsetChangeListener, binding);
}

public void OnScrollChanged1(DependencyObject sender, DependencyPropertyChangedEventArgs e)
{
    double a = (double)e.NewValue;  //获取滚动条位置变化后的属性值
    sv2.ScrollToHorizontalOffset(a);
}

public void OnScrollChanged2(DependencyObject sender, DependencyPropertyChangedEventArgs e)
{
    double a = (double)e.NewValue;
    sv1.ScrollToHorizontalOffset(a);
}

方法二：利用滚动条的ScrollChanged事件，同步两个滚动条的位置。

ScrollViewer sv1, sv2;

private void Window_Loaded(object sender, RoutedEventArgs e)
{
    //分别获取两个DataGrid的ScrollViewer
    sv1 = VisualTreeHelper.GetChild(VisualTreeHelper.GetChild(this.DataGrid1, 0), 0) as ScrollViewer;
    sv2 = VisualTreeHelper.GetChild(VisualTreeHelper.GetChild(this.DataGrid2, 0), 0) as ScrollViewer;

    //关联ScrollChanged事件
    sv1.ScrollChanged += new ScrollChangedEventHandler(sv1_ScrollChanged);
    sv2.ScrollChanged += new ScrollChangedEventHandler(sv2_ScrollChanged);
}

void sv1_ScrollChanged(object sender, ScrollChangedEventArgs e)
{
    sv2.ScrollToHorizontalOffset(sv1.HorizontalOffset);
}

void sv2_ScrollChanged(object sender, ScrollChangedEventArgs e)
{
    sv1.ScrollToHorizontalOffset(sv2.HorizontalOffset);
}