WPF - 动画ListBox.ScrollViewer.Horizo​​ntalOffset？ [英] WPF - Animate ListBox.ScrollViewer.HorizontalOffset?

问题描述

我集合在的ListBox 视觉秒。我需要找到 xPosition位置里面的元素，然后动画的 Horizo​​ntalOffset 的列表框的的ScrollViewer 。基本上我想创建一个动画 ScrollIntoView 方法。

I have a collection of Visuals in a ListBox. I need to find the XPosition of an element inside it and then animate the HorizontalOffset of the ListBox's ScrollViewer. Essentially I want to created an animated ScrollIntoView method.

这给了我几个问题。首先，我怎样才能到的ListBox 取值的ScrollViewer参考？其次，我怎样才能在 ListBox中的任意元素的相对的 xPosition位置或 HozintalOfffset ？

This gives me a couple of problems. Firstly, how can I get a reference to the ListBoxs scrollviewer? Secondly, how can i get the relative XPosition or HozintalOfffset of an arbitrary element in the ListBox?

我不reponding上的的ListBox 本身，所以我不能用鼠标相关属性的任何输入

I'm not reponding to any input on the ListBox itself so I can't use Mouse related properties.

推荐答案

我不认为你将能够使用WPF故事板的动画故事板，因为动画WPF依赖属性。您将需要调用 ScrollViewer.ScrollToHorizo​​ntalOffset（双）滚动。

I don't think you will be able to use a WPF storyboard for the animation because storyboards animate WPF dependency properties. You will need to call ScrollViewer.ScrollToHorizontalOffset(double) to scroll.

您可以尝试创建，在OnDependencyPropertyChanged（）函数调用SetHorizo​​ntalOffset自定义依赖项属性。然后，你可以动画这个属性。

You could try creating a custom dependency property that calls SetHorizontalOffset in the OnDependencyPropertyChanged() function. Then you could animate this property.

public static readonly DependencyProperty ScrollOffsetProperty =
   DependencyProperty.Register("ScrollOffset", typeof(double), typeof(YOUR_TYPE),
   new FrameworkPropertyMetadata(0.0, new PropertyChangedCallback(OnScrollOffsetChanged)));


public double ScrollOffset
{
   get { return (double)GetValue(ScrollOffsetProperty); }
   set { SetValue(ScrollOffsetProperty, value); }
}

private static void OnScrollOffsetChanged(DependencyObject obj, DependencyPropertyChangedEventArgs args)
{
   YOUR_TYPE myObj = obj as YOUR_TYPE;

   if (myObj != null)
      myObj.SCROLL_VIEWER.ScrollToHorizontalOffset(myObj.ScrollOffset);
}

要得到你可以使用VisualTreeHelper搜索列表框的视觉儿童的滚动浏览器。保存到ScrollViewer中的引用，因为你以后会需要它。试试这个：

To get the scroll viewer you can use the VisualTreeHelper to search the visual children of the ListBox. Save a reference to the ScrollViewer because you will need it later. Try this:

public static childItem FindVisualChild<childItem>(DependencyObject obj)
   where childItem : DependencyObject
{
   // Iterate through all immediate children
   for (int i = 0; i < VisualTreeHelper.GetChildrenCount(obj); i++)
   {
      DependencyObject child = VisualTreeHelper.GetChild(obj, i);

      if (child != null && child is childItem)
         return (childItem)child;

      else
      {
         childItem childOfChild = FindVisualChild<childItem>(child);

         if (childOfChild != null)
            return childOfChild;
      }
   }

   return null;
}

该函数返回参数类型的第一视觉孩子。呼叫 FindVisualChild＆LT;的ScrollViewer方式＆gt;（列表框）来获得的ScrollViewer

This function returns the first visual child of the parameter type. Call FindVisualChild<ScrollViewer>(ListBox) to get the ScrollViewer.

最后，请尝试使用 UIElement.TranslatePoint（点，的UIElement）来获得该项目的X位置。呼吁项目这一功能，在0,0通为点，并通过在ScrollViewer中。

Finally, try using UIElement.TranslatePoint(Point, UIElement) to get the X position of the item. Call this function on the item, pass in 0,0 for the point, and pass in the ScrollViewer.

希望这有助于。

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