我有浮动块的TrackBar使用NAudion从网络配乐timeline.Soundtrack发挥。当我开始播放第一首曲目，如果我在start.And仍然改变下一曲目，滑块改变只有当我点击暂停然后播放所有的作品好。不过从n音讯WPF example.I使用的所有代码只改变无障碍modifiers.First时间。
为了充分理解：
第一首曲目 - 滑块工作和运动。
切换到下一首曲目 - 滑块在开始和不动。但它开始按暂停后移动，然后播放。它立即移动到地方，播放的时刻，并继续正常运行。所以每个以下轨道。
VM守则PlayerUserControl：
public class AudioControlVM : ViewModelBase, IDisposable
{
private AudioModel _currentSong;
public AudioModel CurrentSong { get { return _currentSong; } set { _currentSong = value; RaisePropertyChanged("CurrentSong"); } }
private string inputPath, songName;
private string defaultDecompressionFormat;
public IWavePlayer wavePlayer { get; set; }
private WaveStream reader;
public RelayCommand PlayCommand { get; set; }
public RelayCommand PauseCommand { get; set; }
public RelayCommand StopCommand { get; set; }
public DispatcherTimer timer = new DispatcherTimer();
private double sliderPosition;
private readonly ObservableCollection<string> inputPathHistory;
private string lastPlayed;
public AudioControlVM()
{
inputPathHistory = new ObservableCollection<string>();
PlayCommand = new RelayCommand(() => Play());
PauseCommand = new RelayCommand(() => Pause());
StopCommand = new RelayCommand(Stop, () => !IsStopped);
timer.Interval = TimeSpan.FromMilliseconds(500);
timer.Tick += TimerOnTick;
}
public bool IsPlaying => wavePlayer != null && wavePlayer.PlaybackState == PlaybackState.Playing;
public bool IsStopped => wavePlayer == null || wavePlayer.PlaybackState == PlaybackState.Stopped;
public IEnumerable<string> InputPathHistory => inputPathHistory;
const double SliderMax = 10.0;
private void TimerOnTick(object sender, EventArgs eventArgs)
{
if (reader != null)
{
sliderPosition = reader.Position * SliderMax / reader.Length;
RaisePropertyChanged("SliderPosition");
}
}
public double SliderPosition
{
get => sliderPosition;
set
{
if (sliderPosition != value)
{
sliderPosition = value;
if (reader != null)
{
var pos = (long)(reader.Length * sliderPosition / SliderMax);
reader.Position = pos; // media foundation will worry about block align for us
}
RaisePropertyChanged("SliderPosition");
}
}
}
private bool TryOpenInputFile(string file)
{
bool isValid = false;
try
{
using (var tempReader = new MediaFoundationReader(file))
{
DefaultDecompressionFormat = tempReader.WaveFormat.ToString();
InputPath = file;
isValid = true;
}
}
catch (Exception e)
{
}
return isValid;
}
public string DefaultDecompressionFormat
{
get => defaultDecompressionFormat;
set
{
defaultDecompressionFormat = value;
RaisePropertyChanged("DefaultDecompressionFormat");
}
}
public string SongName { get => songName; set
{
songName = value;
RaisePropertyChanged("SongName");
} }
public string InputPath
{
get => inputPath;
set
{
if (inputPath != value)
{
inputPath = value;
AddToHistory(value);
RaisePropertyChanged("InputPath");
}
}
}
private void AddToHistory(string value)
{
if (!inputPathHistory.Contains(value))
{
inputPathHistory.Add(value);
}
}
public void Stop()
{
if (wavePlayer != null)
{
wavePlayer.Stop();
}
}
public void Pause()
{
if (wavePlayer != null)
{
wavePlayer.Pause();
RaisePropertyChanged("IsPlaying");
RaisePropertyChanged("IsStopped");
}
}
public void Play()
{
if (String.IsNullOrEmpty(InputPath))
{
return;
}
if (wavePlayer == null)
{
CreatePlayer();
}
if (lastPlayed != inputPath && reader != null)
{
reader.Dispose();
reader = null;
}
if (reader == null)
{
reader = new MediaFoundationReader(inputPath);
lastPlayed = inputPath;
wavePlayer.Init(reader);
}
wavePlayer.Play();
RaisePropertyChanged("IsPlaying");
RaisePropertyChanged("IsStopped");
timer.Start();
}
private void CreatePlayer()
{
wavePlayer = new WaveOutEvent();
wavePlayer.PlaybackStopped += WavePlayerOnPlaybackStopped;
RaisePropertyChanged("wavePlayer");
}
private void WavePlayerOnPlaybackStopped(object sender, StoppedEventArgs stoppedEventArgs)
{
if (reader != null)
{
SliderPosition = 0;
//reader.Position = 0;
timer.Stop();
}
if (stoppedEventArgs.Exception != null)
{
}
RaisePropertyChanged("IsPlaying");
RaisePropertyChanged("IsStopped");
}
public void PlayFromUrl(string url, string songname)
{
Stop();
inputPath = url;
SongName = songname;
Play();
}
public void Dispose()
{
wavePlayer?.Dispose();
reader?.Dispose();
}
}
播放器的XAML：
<Grid>
<StackPanel Orientation="Horizontal">
<Button Content="Play" Command="{Binding PlayCommand}" VerticalAlignment="Center" Width="75" />
<Button Content="Pause" Command="{Binding PauseCommand}" VerticalAlignment="Center" Width="75" />
<Button Content="Stop" Command="{Binding PlayCommand}" VerticalAlignment="Center" Width="75" />
<Slider VerticalAlignment="Center" Value="{Binding SliderPosition, Mode=TwoWay}" Maximum="10" Width="400" />
<TextBlock Text="{Binding SongName, FallbackValue=Test}" Foreground="White"/>
</StackPanel>
</Grid>
</UserControl>
VM代码，对于新的轨道发送数据：
public class AudioModel
{
public string Artist { get; set; }
public string SongName { get; set; }
public int Duration { get; set; }
public string URL { get; set; }
public RelayCommand PlayThisAudioCommand
{
get;
private set;
}
public AudioModel()
{
PlayThisAudioCommand = new RelayCommand(() => PlayThis());
}
private void PlayThis()
{
if (URL != null)
{
TestVM.AudioConrol.PlayFromUrl(URL, SongName);
}
else;
}
}
它看起来像你可能有一个多线程的问题与你的计时器。事件的顺序似乎是：
这里很重要的一点是，play（）和WavePlayerOnPlaybackStopped（）被调用的顺序。这是非常有可能的事件就在上面的顺序发生了 - 作为wavePlayer提出了另一个线程上PlaybackStopped事件。
总之 - 这WavePlayerOnPlaybackStopped（）在停止播放后您的计时器（）启动它，这就是为什么你的滑块没有更新。按暂停接戏会重新启动定时器，这就是为什么滑块开始暂停后更新。
您可以通过暂时注释掉WavePlayerOnPlaybackStopped（）的代码，这应该可以解决这个问题测试这一点 - 虽然你的滑块不会重置为零当轨迹到达结束或停止。
注：（）的事件wavePlayer.PlaybackStopped主叫wavePlayer.Stop之间的延迟和被提出的原因是由于n音讯使用专用线程来处理重放。当你调用停止（），它必须完成实际停止前处理当前音频缓冲 - 在大多数情况下会导致在几毫秒的延迟。
您可以在WaveOutEvent的DoPlayback方法操作看到这一点：https://github.com/naudio/NAudio/blob/master/NAudio/Wave/WaveOutputs/WaveOutEvent.cs#L147