如何在XAML中将ScrollIntoView用于ListView [英] How to use ScrollIntoView for ListView in xaml

问题描述

我有一个ControlTemplate在ListView中显示项目. ListView有500多个项目.我正在保存状态，并从XML中获取选定的项目，然后将其发送到listview以默认选择它，以供下次导航到屏幕时使用.

I have a ControlTemplate to show Items in ListView. ListView is having 500+ items. I am preserving the state and getting selected item from XML and sending it to listview to select it by default for next navigation to the screen.

我的问题是我如何通过xaml设置选定的项目(可能出现在最后一个，即看不见的项目). ViewModel不知道任何UI控件，因此我无法在ViewModel中应用ScrollIntoView方法.

My problem is How can I set selected item (which may be present in last i.e. out of view) by xaml. ViewModel doesn't know about any UI control, so I cant apply ScrollIntoView method in ViewModel.

我可以使用任何二传手"或样式"来做到这一点吗?

Can I use any Setter or Style to do this?

请提出建议.

推荐答案

我最近使用DataGrid做到了这一点.诀窍是将自定义行为附加到视图.这样.

I've recently done this with a DataGrid. The trick is to attach a custom Behavior to your View. Like that.

<ListView ... >
    <iy:Interaction.Behaviors>
        <ext:ScrollIntoViewBehavior />
    </iy:Interaction.Behaviors>
    ...
</ListView>

和相关的班级:

public class ScrollIntoViewBehavior : Behavior<ListView>
{
    protected override void OnAttached()
    {
        base.OnAttached();
        this.AssociatedObject.SelectionChanged += new SelectionChangedEventHandler(AssociatedObject_SelectionChanged);
    }

    protected override void OnDetaching()
    {
        base.OnDetaching();
        this.AssociatedObject.SelectionChanged -= new SelectionChangedEventHandler(AssociatedObject_SelectionChanged);
    }

    private void AssociatedObject_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        if (sender is ListView)
        {
            ListView grid = (sender as ListView);
            if (grid.SelectedItem != null)
            {
                grid.Dispatcher.BeginInvoke(() =>
                {
                    grid.UpdateLayout();
                    grid.ScrollIntoView(grid.SelectedItem);
                });
            }
        }
    }
}

一些需要注意的事情:

• 添加对System.Windows.Interactivity程序集的引用
• 在视图中添加相应的名称空间:xmlns:iy = http://schemas.microsoft. com/expression/2010/interactivity

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