caliburn.micro - Caliburn 微 : How to add text to the bottom of a list box and display it

Question

我想弄清楚如何将文本添加到列表框的底部并显示它。在带有代码的 WPF 中，我会捕获 ScrollViewer 并对其进行操作，但我无法弄清楚如何使用 Caliburn 来做到这一点...

Answer 1

您有几个选择。

1) 在您的 ViewModel 中，您可以调用 GetView 并将其转换为您的 View 类型并获取对 ScrollViewer 的引用。像这样的东西:

var myView = this.GetView() as MyView;
var myScrollView = myView.MyScrollView;

这很好用，但如果您不想将 View 耦合到 View 模型，则效果不理想。

选项 2) 是实现 IResult，请参阅文档 here .

public class ScrollViewResult : IResult
    {
        public event EventHandler<ResultCompletionEventArgs> Completed = delegate { };

        private ScrollViewResult ()
        {
        }

        public void Execute (ActionExecutionContext context)
        {
            var view = context.View as FrameworkElement;
            var scrollViewer = FindVisualChild<ScrollViewer>(view);

            //do stuff to scrollViewer here

            Completed (this, new ResultCompletionEventArgs { });
        }

        private static TChildItem FindVisualChild<TChildItem> (DependencyObject obj)
            where TChildItem : DependencyObject
        {
            for (var i = 0; i < VisualTreeHelper.GetChildrenCount (obj); i++)
            {
                var child = VisualTreeHelper.GetChild (obj, i);
                if (child != null && child is TChildItem)
                    return (TChildItem)child;

                var childOfChild = FindVisualChild<TChildItem> (child);
                if (childOfChild != null)
                    return childOfChild;
            }
            return null;
        }

        //this isn't required of course but comes in handy for 
        //having a static method and passing parameters to the
        //ctor of the IResult
        public static IResult DoSomething ()
        {
            return new ScrollViewResult ();
        }

然后你可以这样调用它:

public IEnumerable<IResult> SomeAction()
        {
            yield return ScrollViewResult.DoSomething();
        }