如何從上下文菜單中的選項調用longlistselector事件

Question

private void Deleting(object sender, RoutedEventArgs e) 
{ 
    MessageBoxResult message = MessageBox.Show(
     "The file will be permanently deleted. Continue?", 
     "Delete File", 
     MessageBoxButton.OKCancel 
    ); 

    if (message == MessageBoxResult.OK) 
    { 
     LongListSelector selector = sender as LongListSelector; 

     SoundData data1 = selector.SelectedItem as SoundData; 

     //control goes inside this block 
     if (selector == null) 
     { 
      return; 
     } 

     if (data1 == null) 
      return; 
    } 
} 

我必須能夠從長列表選擇器訪問該數據。刪除事件處理程序來自上下文菜單按鈕

此代碼能夠引用longlistselector中的選項。由於Venkatapathi拉朱求助

 public void Deleting(object sender, RoutedEventArgs e) 
     { 
     SoundData data1 = (sender as MenuItem).DataContext as SoundData; 

     MessageBoxResult message = MessageBox.Show(
     "The file will be permanently deleted. Continue?", 
     "Delete File", 
     MessageBoxButton.OKCancel 
     ); 

     if (message == MessageBoxResult.OK) 
     { 

私人無效LongListSelector_SelectionChanged（對象發件人，SelectionChangedEventArgs E） { LongListSelector選擇=發送者作爲LongListSelector;

 if (selector == null) 
      return; 

     SoundData data = selector.SelectedItem as SoundData; 

     if (data == null) 
      return; 

     if (File.Exists(data.FilePath)) 
     { 
      AudioPlayer.Source = new Uri(data.FilePath, UriKind.RelativeOrAbsolute); 
     } 
     else 
     { 
      using (var storageFolder = IsolatedStorageFile.GetUserStoreForApplication()) 
      { 
       //Breakpoint 
     using (var stream = new IsolatedStorageFileStream(data.FilePath, FileMode.Open, storageFolder)) 
       { 
        AudioPlayer.SetSource(stream); 
       } 
      } 
     } 

我收到此錯誤信息 型「System.IO.IsolatedStorage.IsolatedStorageException」的異常出現在mscorlib.ni.dll但在用戶代碼中沒有處理

Answer 1

這將爲你工作。 contextmenu的DataContext屬性爲您提供longlistselector的menuItem。

可以執行刪除操作，如下圖所示：

private void Deleting(object sender, RoutedEventArgs e) 
{ 
    SoundData data1 = (sender as MenuItem).DataContext as SoundData; 

    MessageBoxResult message = MessageBox.Show(
    "The file will be permanently deleted. Continue?", 
    "Delete File", 
    MessageBoxButton.OKCancel 
    ); 

    if (message == MessageBoxResult.OK) 
    { 
     //Call the method which deletes the data and pass data1 to it. 
    } 
} 

我相信你是從鮑勃·泰伯的視頻學習。保持下去。

private void Delete_Click(object sender, RoutedEventArgs e) 
    { 

     SoundData data = (sender as MenuItem).DataContext as SoundData; 
     MessageBoxResult result = MessageBox.Show("Do you want to delete this item ?", "Are you sure ?", MessageBoxButton.OKCancel); 

     if (result == MessageBoxResult.OK) 
     { 
      if (data == null) 
      { 
       MessageBox.Show("The file doesn't exist"); 
       return; 
      } 

      using (var storageFolder = IsolatedStorageFile.GetUserStoreForApplication()) 
      { 
       if (storageFolder.FileExists(data.FilePath)) 
       { 
        storageFolder.DeleteFile(data.FilePath); 

        App.ViewModel.CustomSounds.Items.Remove(data); 

        // Save the list of CustomSounds to IsolatedStorage.ApplicationSettings 
        var JsonData = JsonConvert.SerializeObject(App.ViewModel.CustomSounds); 

        IsolatedStorageSettings.ApplicationSettings[SoundModel.CustomSoundKey] = JsonData; 
        IsolatedStorageSettings.ApplicationSettings.Save(); 

        App.ViewModel.IsDataLoaded = false; 
        App.ViewModel.LoadData(); 

       } 
       else 
       { 
        MessageBox.Show("File doesn't exist"); 
        return; 
       } 
      } 
     } 
     else 
     { 
      return; 
     } 
    } 

Answer 2

我認爲你可以做它：

private void Deleting(object sender, RoutedEventArgs e) 
{ 
    MessageBoxResult message = MessageBox.Show(
     "The file will be permanently deleted. Continue?", 
     "Delete File", 
     MessageBoxButton.OKCancel 
    ); 

    if (message == MessageBoxResult.OK) 
    {     
     SoundData data1 = myLongListSelector.SelectedItem as SoundData; 

     if (data1 == null) 
      return; 

     //control goes inside this block 
    } 
} 

還記得設置selectoed項目爲空（在方法的結束），因爲它的刪除：

myLongListSelector.SelectedItem = null;