リストの値のない繰り返し（C＃の）

Question

私は、ユーザーがMainPage.xaml

<StackPanel Grid.Row="0" Grid.Column= "0" HorizontalAlignment= "Left" VerticalAlignment= "Top" > 
    < Button x:Name= "FavoriteButton" FontFamily= "Segoe MDL2 Assets" 
      Content= "&#xE006;" BorderBrush= "Transparent" FontSize= "28" 
      Foreground= "{StaticResource PhoneForegroundBrush}" 
      Style= "{StaticResource ButtonStyle1}" Click= "FavoriteButton_Click" /> 
</ StackPanel > 

<StackPanel Grid.Row="0" Grid.Column= "2" HorizontalAlignment= "Left" VerticalAlignment= "Top" > 
    < Button x:Name= "FavoriteListButton" FontFamily= "Segoe MDL2 Assets" 
      Content= "&#xEA55;" BorderBrush= "Transparent" FontSize= "28" 
      Foreground= "{StaticResource PhoneForegroundBrush}" 
      Style= "{StaticResource ButtonStyle1}" Click= "FavoriteListButton_Click" /> 
</ StackPanel > 

C#

private void FavoriteButton_Click(object sender, RoutedEventArgs e) 
    { 

     listobj.Add(new MyData { AnswerName = AnswerTextBlock.Text }); 


     using (IsolatedStorageFileStream fileStream = Settings1.OpenFile("MyStoreItems", FileMode.Create)) 
     { 
      DataContractSerializer serializer = new DataContractSerializer(typeof(MyDataList)); 
      serializer.WriteObject(fileStream, listobj); 

     } 
    } 

    private void FavoriteListButton_Click(object sender, RoutedEventArgs e) 
    { 
     if(FavoriteListBox.Visibility.Equals(Visibility.Collapsed)) 
     { 
      FavoriteListBox.Visibility = Visibility.Visible; 
     } 
     else if(FavoriteListBox.Visibility.Equals(Visibility.Visible)) 
     { 
      FavoriteListBox.Visibility = Visibility.Collapsed; 
     }   
    } 

やリストボックス

XAMLでTextblockからテキストを保存することができますお気に入りのリストボックスを作成

 <StackPanel Grid.Column="1" Grid.Row="0" HorizontalAlignment="Center" VerticalAlignment="Top">     
      <ListBox x:Name="FavoriteListBox" Visibility="Collapsed" 
        SelectionChanged="FavoriteListBox_SelectionChanged" 
        HorizontalAlignment="Stretch" 
        VerticalAlignment="Top" Opacity="1" 
        Background="{StaticResource PhoneBackgroundBrush}" Foreground="{StaticResource PhoneForegroundBrush}" 
        Height="300" Width="250"> 
       <ListBox.ItemTemplate> 
        <DataTemplate> 
         <TextBlock Visibility="Visible" x:Name="FavoriteListBoxTextBlock" 
            FontSize="35" Foreground="Black" Text="{Binding AnswerName}"/> 
        </DataTemplate> 
       </ListBox.ItemTemplate> 
      </ListBox> 
     </StackPanel> 

C#

public partial class MainPage : PhoneApplicationPage 
{ 
    IsolatedStorageFile Settings1 = IsolatedStorageFile.GetUserStoreForApplication(); 
    MyDataList listobj = new MyDataList(); 

    public MainPage() 

    { 
     InitializeComponent(); 

     this.Loaded += MainPage_Loaded; 

     if (Settings1.FileExists("MyStoreItems")) 
     { 
      using (IsolatedStorageFileStream fileStream = Settings1.OpenFile("MyStoreItems", FileMode.Open)) 
      { 
       DataContractSerializer serializer = new DataContractSerializer(typeof(MyDataList)); 
       listobj = (MyDataList)serializer.ReadObject(fileStream); 

      } 
     } 


     FavoriteListBox.ItemsSource = listobj;//binding isolated storage list data 



    private void MainPage_Loaded(object sender, RoutedEventArgs e) 
    { 
     if (Settings1.FileExists("MyStoreItems"))//loaded previous items into list 
     { 
      using (IsolatedStorageFileStream fileStream = Settings1.OpenFile("MyStoreItems", FileMode.Open)) 
      { 
       DataContractSerializer serializer = new DataContractSerializer(typeof(MyDataList)); 
       listobj = (MyDataList)serializer.ReadObject(fileStream); 

      } 
     } 
    } 

    public class MyData 
    { 
     public string AnswerName { get; set; }    
    } 
    public class MyDataList : ObservableCollection<MyData> //for storing mydata class items with type of list 
    { 

    } 

いくつかのテキストは、お気に入りボタンをクリックしたときに、分離ストレージに行く示しTextboxのすべてのテキスト。同じテキストが既にリストに存在していても同じテキストをコピーするので、お気に入りのボタンをクリックしたときに、リストにテキストがすでに存在するかどうかを確認する必要があります。存在する場合は置換するかコピーしないでください再び。どのようにこれを行うには。

Answer 1

あなたは非常に簡単にFavoriteButton_Clickメソッドの開始時にLINQ Anyクエリを使用して重複をチェックすることができます。

private void FavoriteButton_Click(object sender, RoutedEventArgs e) 
{ 
    //check if there is any item with the same text 
    //in which case do not continue 
    if (listobj.Any(l => l.AnswerName == AnswerTextBlock.Text)) return; 

    listobj.Add(new MyData { AnswerName = AnswerTextBlock.Text }); 


    using (IsolatedStorageFileStream fileStream = Settings1.OpenFile("MyStoreItems", FileMode.Create)) 
    { 
     DataContractSerializer serializer = new DataContractSerializer(typeof(MyDataList)); 
     serializer.WriteObject(fileStream, listobj); 

    } 
}