如何在Xamarin Forms中的滚动视图中检测击中网格底部 [英] How to detect hitting the bottom of a grid within a scrollview in Xamarin Forms

问题描述

我正在使用Xamarin.Forms在GridView(在ScrollView中)中显示来自Websource的项目.

I am using Xamarin.Forms to display Items from a Websource in a Grid (within a ScrollView).

当用户点击网格底部时，我想加载更多项目并将其添加到网格中.我知道通常使用ListView首选以这种方式显示数据(并且ListView具有ItemAppearing事件)，但可悲的是，我必须使用网格.

When the user hits the bottom of the grid, i want to load more items and add them to the grid. I know that usually a ListView is preferred for displaying data in this fashion (and that ListView has an ItemAppearing event) but sadly i have to use a grid.

如果有帮助，我可以发布一些代码，但不确定在这里是否有必要.

If it helps, i could post some code, but im not sure if that is necessary here.

先谢谢了 这是我非常无聊的布局文件:

Thanks in advance here is my really boring layout file:

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="MyProject.MyNamespace.LayoutName"
             SizeChanged="OnPageSizeChanged">
  <ScrollView >
    <AbsoluteLayout x:Name="myLayout">
      <Grid x:Name="GridForItems" RowSpacing="6" ColumnSpacing="6">
      </Grid>
    </AbsoluteLayout>
  </ScrollView>
</ContentPage>

我以编程方式添加所有行，列和项目.

I add all the rows, columns and items programmatically.

推荐答案

由于我对原问题(如何检测滚动视图的底部的底部)没有令人满意的答案，所以我有了在网络上其他任何地方都找不到解决方案，我将发布解决方法.

Since i had not gotten a satisfying answer to my original question (how to detect hitting the bottom of a scrollview) and i have not found a solution anywhere else on the net i am going to post how i solved this.

请注意，这可能不是一个很好的解决方案，如果您有更好的答案，请张贴它，我会接受它作为最佳答案.

Note that this is probably the not an elegant solution and, if you have a better answer, please post it and i will accept it as the best answer.

我所做的是实现ScrollView的Scrolled Event的委托.

What i did was implement a delegate for the Scrolled Event of ScrollView.

myScrollView.Scrolled += (sender, e) => { onScrolled(); };

在onScrolled中，我有以下if子句来确定我是否触及了ScrollView的底部:

Within my onScrolled i have the following if-clause to determine whether i have hit the bottom of the ScrollView:

 private void onScrolled()
 {
    if(myScrollView.ScrollY >= myScrollView.ContentSize.Height - myScrollView.Height)
    {
      //Handle hitting the bottom
    }
 }

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