问题描述

我正在使用滑块来控制正在播放的 MediaElement 的位置.我已经实现了 ValueChanged 事件来同步滑块的位置和值.因此，当我在 Thumb 上拖动时，MediaElement 的位置也会发生变化.但是，这会造成糟糕的用户体验.理想的情况应该是，在用户完成滑动后，MediaElement 会跳转到最终位置.所以我正在寻找像 AfterSliding 这样的事件/处理程序.

I am using a slider to control the position of a playing MediaElement. I have implemented the ValueChanged event to synchronize the position and the value of slider. So when I am dragging on the Thumb, the position of MediaElement also changes. However, this creates bad user experience. The ideal case should be like, after user finishes sliding, MediaElement jumps to that final position. So I am looking for events/handlers like AfterSliding.

我见过像使用 OnThumbDragCompleted 这样的解决方案.但是，这些问题是关于 WPF 的，我在 UWP 中找不到这样的问题.有人有解决方法吗?

I have seen solutions like using OnThumbDragCompleted. However, those questions are about WPF and I cannot find such in UWP. Does anyone have a workaround?

当前:

    private void ProgressBar_ValueChanged(object sender, RangeBaseValueChangedEventArgs e)
    {
        MediaPlayer.Position = TimeSpan.FromSeconds(e.NewValue);
        LeftTimeTextBlock.Text = MusicDurationConverter.ToTime((int)e.NewValue);
    }

预期:

    private void ProgressBar_ValueChanged(object sender, RangeBaseValueChangedEventArgs e)
    {
        if (!isDragging || slidingFinished) MediaPlayer.Position = TimeSpan.FromSeconds(e.NewValue);
        LeftTimeTextBlock.Text = MusicDurationConverter.ToTime((int)e.NewValue);
    }

---更新---

我有一个每秒计时的计时器，但是当我点击滑块(不是拇指)区域时，并不总是触发点击事件，因此拇指会在点击的位置和它的新位置之间来回移动.我该如何解决它，以便当用户仍然握住拇指时，它会保持在点击位置?我猜这个 tapped 事件可能不是我应该使用的.

I have a timer that ticks every second, but when I tap on the slider (not the thumb) area, the tapped event is not always fired so the thumb will go back and forth between the clicked place and its new position. How can I resolve it so that when user is still holding the thumb, it stays put at the clicked position? I guess the tapped event maybe is not what I should use.

    public void Tick()
    {
        if (ShouldUpdate && !SliderClicked)
        {
            MediaSlider.Value = MediaControl.Player.PlaybackSession.Position.TotalSeconds;
        }
        SliderClicked = false;
    }

    private void MediaSlider_Tapped(object sender, TappedRoutedEventArgs e)
    {
        Debug.WriteLine("Tapped");
        MediaControl.SetPosition(MediaSlider.Value);
        SliderClicked = true;
    }

    private void MediaSlider_ManipulationCompleted(object sender, ManipulationCompletedRoutedEventArgs e)
    {
        MediaControl.SetPosition(MediaSlider.Value);
        ShouldUpdate = true;
        Debug.WriteLine("Completed");
    }

    private void MediaSlider_ManipulationStarted(object sender, ManipulationStartedRoutedEventArgs e)
    {
        ShouldUpdate = false;
        Debug.WriteLine("Started");
    }

推荐答案

Slider 有 ManipulationCompleted 事件.当对 UIElement 的操作完成时发生.您可以订阅它以侦听 Slider 是否完成.同时，如果要处理操作事件，则需要将 ManipulationMode 设置为 System 或 None 以外的值.

Slider has ManipulationCompleted event.Occurs when a manipulation on the UIElement is complete.You can subscribe it to listen if Slider is completed.At the same time,you need to set the ManipulationMode to a value other than System or None if want to handle manipulation events.

在 XAML 中:

<Slider Name="timelineSlider" ManipulationCompleted="Slider_ManipulationCompleted" ManipulationMode="All" ValueChanged="SeekToMediaPosition" />

在 C# 中:

private void Slider_ManipulationCompleted(object sender, ManipulationCompletedRoutedEventArgs e)
        {​
            Slider MySlider = sender as Slider;​
            myMediaElement.Position = TimeSpan.FromSeconds(MySlider.Value);​
            LeftTimeTextBlock.Text = MusicDurationConverter.ToTime((int)e.NewValue);​
        }

更新:

你可以订阅ValueChanged和ManipulationStarting事件.我发现当你拖动Thumb时，它会先触发starting事件，然后是valuechanged.如果你只点击，它会先触发valuechange然后starting事件.

You can subscribe ValueChanged and ManipulationStarting event.I find when you drag the Thumb,it will first trigger the starting event and then valuechanged.If you only click,it will first trigger the valuechange and then starting event.

在 XAML 中:

<Slider Name="timelineSlider" ManipulationStarting="TimelineSlider_ManipulationStarting"  ManipulationCompleted="Slider_ManipulationCompleted" ManipulationMode="All" ValueChanged="SeekToMediaPosition" Width="70"/>

在 C# 中:

您可以声明一个oldValue属性来保存Slider的值.触发开始事件时，可以比较oldValue和当前值.如果相等，则拖动Thumb.

You can declare a oldValue property to save the value of Slider.When trigger the starting event,you can compare oldValue and the current value.If equal,you drag the Thumb.

private double oldValue;

private void SeekToMediaPosition(object sender, RangeBaseValueChangedEventArgs e)
        {
            if (isTap==true)
            {
                ...//tap
            }
            else
            {

            }
            oldValue = timelineSlider.Value;
        }
private void Slider_ManipulationCompleted(object sender, ManipulationCompletedRoutedEventArgs e)
        {

            Slider MySlider = sender as Slider;
            double s = MySlider.Value;
            isTap = true;
        }

        private void TimelineSlider_ManipulationStarting(object sender, ManipulationStartingRoutedEventArgs e)
        {
            if (oldValue == timelineSlider.Value) {
                //tuozhuai
                isTap = false;
            }
            else{
                isTap = true;
            }
        }

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