private void BtnVideoPlay_Click(object sender, RoutedEventArgs e) { if (this.VideoViewer == null || !this.VideoViewer.IsLoaded) { this.VideoViewer = new VideoPlayWindow(); this.VideoViewer.Show(); WindowInteropHelper wnd = new WindowInteropHelper(this.VideoViewer); this.MyVideoPlayer = new VideoPlayer(wnd.Handle, @"output.mp4"); } bool result = this.MyVideoPlayer.Play(); if (!result) { MessageBox.Show("動画の再生に失敗しました。", "Error"); } this.VideoState = PlayerState.Playing; this.NotifyPropertyChanged("IsVideoPlayButtonEnable"); this.NotifyPropertyChanged("IsVideoPauseButtonEnable"); this.NotifyPropertyChanged("IsVideoStopButtonEnable"); }