如果您阅读CarouselView的文档，它同时具有Position（当前索引）和CurrentItem（实际对象）的属性

解决方案

我用这个来解决我的问题。我把我的代码留在这里了，也许它能帮到别人。
代码页.xaml：

<StackLayout Padding="5">
    <CarouselView x:Name="carousel" HeightRequest="600" IndicatorView="{x:Reference contImgs}" PositionChanged="OnPositionChanged">
        <CarouselView.ItemTemplate>
            <DataTemplate>
                <Image x:Name="activeImg" Source="{Binding Source}" Aspect="AspectFill"></Image>
            </DataTemplate>
        </CarouselView.ItemTemplate>
    </CarouselView>
    <IndicatorView x:Name="contImgs" IndicatorColor="#bbb" SelectedIndicatorColor="#000" IndicatorSize="12" IndicatorsShape="Circle"></IndicatorView>
    <ImageButton Source="drawable/icon_trash.png" WidthRequest="100" Clicked="btnDeleteImg" HeightRequest="100" AbsoluteLayout.LayoutBounds="0.98,0.07,50,50" AbsoluteLayout.LayoutFlags="PositionProportional"></ImageButton>
</StackLayout>

代码页. xaml.cs：

private List<Image> imgsCarrousel = new List<Image>();
private int currentPositionImg;
    private void btnDeleteImg(object sender, EventArgs e)
    {
        imgsCarrousel.Remove(currentPositionImg);
        carousel.ItemsSource = imgsCarrousel.ToArray();
    }
    void OnPositionChanged(object sender, PositionChangedEventArgs e)
    {
        int previousItemPosition = e.PreviousPosition;
        currentPositionImg = e.CurrentPosition;
    }