2
第一篇文章，所以要溫柔和抱歉的長篇文章，但要儘可能提供更多的細節。WPF Mediaelement mediaopened事件沒有從代碼背後觸發，但從按鈕點擊處理程序發起
我有一個用戶控件內的MediaElement控件，將LoadedBehaviour屬性設置爲手動，見下文。當我點擊「打開」按鈕時，處理程序代碼包括播放媒體，以便我可以在MediaOpened事件處理程序中準備好持續時間，它可以成功執行。當我只需要媒體長度時，MediaOpened處理程序停止播放。
我也想在程序的開始加載一個播放列表，並用信息填充一個數據網格，其中一個元素是媒體的長度。
XAML
<MediaElement Grid.Row="5" Name="MediaEL" Grid.ColumnSpan="6" MediaOpened="MediaEL_MediaOpened" LoadedBehavior="Manual" Height="169" />
<DataGrid Grid.Row="1" Grid.ColumnSpan="6" Name="dgPlayList" AutoGenerateColumns="False" Height="300" >
<DataGrid.Columns>
<DataGridTextColumn Binding="{Binding Position}" Header="#" Width="30"/>
<DataGridTextColumn Binding="{Binding Title}" Header="Title" Width="182"/>
<DataGridTextColumn Binding="{Binding Time}" Header="Time" Width="50"/>
<DataGridCheckBoxColumn Binding="{Binding Dnp}" Header="Dnp" Width="35"/>
<DataGridTextColumn Binding="{Binding Location}" Visibility="Hidden" />
</DataGrid.Columns>
</DataGrid>
C＃
private void btnOpen_Click(object sender, RoutedEventArgs e)
{
System.Windows.Forms.OpenFileDialog ofd = new System.Windows.Forms.OpenFileDialog();
if (ofd.ShowDialog() == System.Windows.Forms.DialogResult.OK)
{
MediaEL.Source = new Uri(ofd.FileName);
btnPlay.IsEnabled = true;
MediaEL.Visibility = Visibility.Hidden;
SettingTime = true;
MediaEL.Play();
}
}
private void MediaEL_MediaOpened(object sender, RoutedEventArgs e)
{
if (MediaEL.NaturalDuration.HasTimeSpan)
{
TimeSpan ts = MediaEL.NaturalDuration.TimeSpan;
Length.Content = FormatLength(ts.TotalSeconds); // make it look like 00:00:00
seekBar.Maximum = ts.TotalSeconds;
seekBar.SmallChange = 1;
seekBar.LargeChange = Math.Min(10, ts.Seconds/10);
}
if (!SettingTime)
timer.Start();
else
{
SettingTime = false;
MediaEL.Stop();
MediaEL.Visibility = Visibility.Visible;
MediaEL.Close();
}
}
dgPlayList.ItemsSource = LoadPlayListData（）;在窗口加載的方法中調用
。
我已經在foreach語句下面的方法中註釋掉了，直到我找到一個工作。
現在的問題是，當試圖獲得媒體長度來填充數據網格時間列MediaOpened事件不會觸發，我不明白爲什麼不，並已經用盡了主題的搜索。
任何想法將不勝感激！
謝謝，吉姆
C＃
private ObservableCollection<PlayListEntry> LoadPlayListData()
{
var playListEntries = new ObservableCollection<PlayListEntry>();
var position = 1;
var bPlay = false;
var doc = new XmlDocument();
doc.Load(System.IO.Path.GetDirectoryName(Assembly.GetExecutingAssembly().GetName().CodeBase) + @"/mpcplaylist.xml");
var root = doc.DocumentElement;
var nodes = root.SelectNodes("/playlist/media");
XmlNode node = nodes[0];
if (node.InnerXml.Contains("title"))
{
var xmlElement = node["title"];
if (xmlElement != null)
Title = xmlElement.InnerText;
}
if (node.InnerXml.Contains("artist"))
{
var xmlElement = node["artist"];
if (xmlElement != null)
Artist = xmlElement.InnerText;
}
if (node.InnerXml.Contains("location"))
{
var xmlElement = node["location"];
if (xmlElement != null)
Location = xmlElement.InnerText;
}
if (node.InnerXml.Contains("include"))
{
var xmlElement = node["include"];
if (xmlElement != null)
Include = xmlElement.InnerText;
}
if (Include == "No")
bPlay = true;
else
bPlay = false;
//foreach (XmlNode node in nodes)
//{
// if (node.InnerXml.Contains("title"))
// {
// var xmlElement = node["title"];
// if (xmlElement != null)
// Title = xmlElement.InnerText;
// }
// if (node.InnerXml.Contains("artist"))
// {
// var xmlElement = node["artist"];
// if (xmlElement != null)
// Artist = xmlElement.InnerText;
// }
// if (node.InnerXml.Contains("location"))
// {
// var xmlElement = node["location"];
// if (xmlElement != null)
// Location = xmlElement.InnerText;
// }
// if (node.InnerXml.Contains("include"))
// {
// var xmlElement = node["include"];
// if (xmlElement != null)
// Include = xmlElement.InnerText;
// }
// if (Include == "No")
// bPlay = true;
// else
// bPlay = false;
MediaEL.Source = new Uri(Location);
SettingTime = true;
MediaEL.Play();
Medialength = Length.Content.ToString();
playListEntries.Add(new PlayListEntry()
{
Dnp = bPlay,
Position = position++,
Time = Medialength,
Title = Title,
Location = Location
});
//}
return playListEntries;
}
很奇怪，你沒有得到任何反饋這裏...我有類似的問題，並會盡快給你當我找到一個解決方案。 – Sheridan