当检测列表视图WPF滚动条是底部？ [英] Detect when WPF listview scrollbar is at the bottom?

问题描述

有没有一种方法来检测，如果从的ScrollViewer 在的ListView 已经达到了底部的滚动条虚拟滚动空间？我想检测到这种从服务器获取更多的项目投入绑定的ObservableCollection 在的ListView 。

Is there a way to detect if the scrollbar from the ScrollViewer in a ListView has reached the bottom of the virtual scroll space? I would like to detect this to fetch more items from the server to put into the bound ObservableCollection on the ListView.

现在我这样做：

private void currentTagNotContactsList_scrollChanged(object sender, ScrollChangedEventArgs e) {

    ListView v = (ListView)sender;


    if (e.VerticalOffset + e.ViewportHeight == e.ExtentHeight) {
        Debug.Print("At the bottom of the list!");
    }

}

这甚至正确吗？我还需要垂直滚动条来区分导致事件和水平滚动条导致它（即我不想让生成调用服务器，如果你在盒子的底部水平滚动）。

Is this even correct? I also need to differentiate between the vertical scrollbar causing the event and the horizontal scrollbar causing it (i.e. I don't want to keep generating calls to the server if you scroll horizontally at the bottom of the box).

感谢。

推荐答案

我想通了。看来我应该已经从滚动条（＆LT; ListView控件ScrollBar.Scroll =currentTagNotContactsList_Scroll在XAML）获取事件本身，而不是浏览器。这工作，但我只是要搞清楚一个方式，以避免事件处理程序被反复调用一次的滚动条了。也许一个定时器将是很好的：

I figured it out. It seems I should have been getting events from the ScrollBar (<ListView ScrollBar.Scroll="currentTagNotContactsList_Scroll" in XAML) itself, rather than the viewer. This works, but I just have to figure a way to avoid the event handler being called repeatedly once the scrollbar is down. Maybe a timer would be good:

private void currentTagNotContactsList_Scroll(object sender, ScrollEventArgs e) {

    ScrollBar sb = e.OriginalSource as ScrollBar;

    if (sb.Orientation == Orientation.Horizontal)
        return;

    if (sb.Value == sb.Maximum) {
        Debug.Print("At the bottom of the list!");

    }

}

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