滚动到带有标题的Xamarin Forms ListView的开始 [英] Scrolling to start of Xamarin Forms ListView with header

问题描述

在Xamarin Forms中滚动到ListView的顶部时遇到一些麻烦.我可以通过调用ScrollTo并传递第一项来滚动到第一项.问题是，当列表具有标题项时，我找不到滚动到标题的方法.这可能吗?我能想到的唯一解决方法是不使用标题，而在ItemSource列表的开头仅包含另一个用作标题的项目，但我更愿意在可能的情况下使用标题.谢谢.

I'm having some trouble scrolling to the top of a ListView in Xamarin Forms. I can scroll to the first item by calling ScrollTo and passing the first item. The problem is that when the list has a header item, I can't find a way to scroll to the header. Is this possible? The only work around I can think of is to not use the header and just have another item at the start of the ItemSource list that acts as a header but I'd rather use the header if possible. Thanks.

推荐答案

所以我现在已经解决了这个问题.我的解决方案是继承ListView的子类，并添加一个公共ScrollToTop方法，该方法在调用时将调用内部ScrollToTopRequestedEvent.然后，我在每个平台上将ListViewRenderer子类化，并为该事件注册.

So I've solved this myself now. My solution was to subclass ListView and add a public ScrollToTop method which invokes an internal ScrollToTopRequestedEvent when called. I then subclassed the ListViewRenderer on each platform and registered for the event.

然后在Android渲染器中调用Control.SmoothScrollToPositionFromTop(0，0)滚动到顶部.

In the Android renderer I'm then calling Control.SmoothScrollToPositionFromTop(0, 0) to scroll to top.

在渲染的iOS中，我调用Control.ScrollRectToVisible(new CoreGraphics.CGRect(0，0，1，1)，true).

In the iOS rendered I'm calling Control.ScrollRectToVisible(new CoreGraphics.CGRect(0, 0, 1, 1), true).

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