使用MediaElement和Caliburn Micro在Silverlight中播放声音

Question

如何使用Caliburn Micro在Silverlight中播放MP3？

需要基于ViewModel中的布尔变量执行MediaElement的“play（）”方法。

提前感谢！

- Steven Rogers

Answer 1

使用一个 IResult。 示例代码 编辑：基于布尔值，如果您描述这个情况，我可以修改示例。

视图：

<Grid>
        <MediaElement AutoPlay="False"
                      Source="../Assests/Kalimba.mp3"></MediaElement>
        <Button x:Name="Play"
                Content="Play"
                Height="50"
                Width="150" />
    </Grid>

ViewModel:

public class MediaViewModel : Screen
    {
        public MediaViewModel()
        {
            DisplayName = "Media Sample";
        }

        public IEnumerable<IResult> Play()
        {
            var result = new PlayMediaResult();
            yield return result;
        }
    }

PlayMediaResult:

 public class PlayMediaResult : IResult
    {
        public void Execute(ActionExecutionContext context)
        {
            var view = context.View as FrameworkElement;
            var mediaElement = FindVisualChild<MediaElement>(view);

            if (mediaElement != null)
            {
                mediaElement.Play();
                Completed(this, new ResultCompletionEventArgs {});
            }

            Completed(this, new ResultCompletionEventArgs {});
        }

        public event EventHandler<ResultCompletionEventArgs> Completed;

        public 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;
        }
    }
}

- Derek Beattie