Question

大家好我有一个列表框，我在XML文件中保存列表框选中的项目工作正常，但问题是，当我将关闭我的应用程序并重新打开并向列表框添加更多值时，我的前一个值被删除表单xml文件和列表框也是我如何在xml文件中保存我当前的添加值和以前的值我正在使用以下代码：

和iam使用以下代码

<Grid x:Name="ContentPanel" Grid.Row="2" Margin="15,10,15,0">
    <ListBox Name="list_location" Tap="list_location_Tap"  Foreground="Black">
        <ListBox.ItemTemplate>
            <DataTemplate>
                <TextBlock x:Name="item_name" Text="{Binding description, Mode=OneWay}" Padding="5,15,5,15" TextWrapping="Wrap" FontSize="{StaticResource PhoneFontSizeLarge}"/>
            </DataTemplate>
        </ListBox.ItemTemplate>
    </ListBox>

    <ListBox Name="list_locationAdd" Background="Red"  Foreground="Black" Visibility="Collapsed">
        <ListBox.ItemTemplate>
            <DataTemplate>
                <TextBlock x:Name="item_name" Text="{Binding description, Mode=OneWay}" Padding="5,15,5,15" TextWrapping="Wrap" FontSize="{StaticResource PhoneFontSizeLarge}"/>
            </DataTemplate>
        </ListBox.ItemTemplate>
    </ListBox>
</Grid>

我的后端代码如下：

 XmlWriterSettings x_W_Settings = new XmlWriterSettings();
 x_W_Settings.Indent = true;
 using (IsolatedStorageFile ISF = IsolatedStorageFile.GetUserStoreForApplication())
 {
     using (IsolatedStorageFileStream stream = ISF.OpenFile(filename, FileMode.Create))
     {
         XmlSerializer serializer = new XmlSerializer(typeof(ObservableCollection<Prediction>));
         using (XmlWriter xmlWriter = XmlWriter.Create(stream, x_W_Settings))
         {                                        
             data.Add(new Prediction() { description = App.professionalId });
             list_locationAdd.ItemsSource = data;
             serializer.Serialize(xmlWriter, data);
         }
     }
 }

 protected override void OnNavigatedTo(NavigationEventArgs e)
    {
        try
        {
            if (list_locationAdd != null)
            {
                using (IsolatedStorageFile ISF = IsolatedStorageFile.GetUserStoreForApplication())
                {
                    using (IsolatedStorageFileStream str = ISF.OpenFile(filename, FileMode.Open))
                    {
                        XmlSerializer serializer = new XmlSerializer(typeof(ObservableCollection<Prediction>));
                        ObservableCollection<Prediction> data = (ObservableCollection<Prediction>)serializer.Deserialize(str);
                        if (list_locationAdd != null)
                        {
                            this.list_locationAdd.ItemsSource = data;
                            list_locationAdd.Visibility = Visibility.Visible;
                        }                            
                    }
                }
            }
        }
        catch (Exception ex)
        {

        }          
    }

Answer 1

按以下方式更改代码：

using (IsolatedStorageFile ISF = IsolatedStorageFile.GetUserStoreForApplication())
 {
     using (IsolatedStorageFileStream stream = ISF.OpenFile(filename, FileMode.Create))
     {
         XmlSerializer serializer = new XmlSerializer(typeof(ObservableCollection<Prediction>));
         using (XmlWriter xmlWriter = XmlWriter.Create(stream, x_W_Settings))
         {                                        
             data.Add(new Prediction() { description = App.professionalId });
             list_locationAdd.ItemsSource = data;
             serializer.Serialize(xmlWriter, data);
         }
 }

更新当前代码：

IsolatedStorageFile isoStore = IsolatedStorageFile.GetStore(IsolatedStorageScope.User | IsolatedStorageScope.Assembly, null, null);
if (isoStore.FileExists(filename))
{       
    try
    {           
        using (IsolatedStorageFileStream isoStream = new IsolatedStorageFileStream(filename, System.IO.FileMode.Open, System.IO.FileAccess.Read, isoStore))
        {
            XmlSerializer serializer = new XmlSerializer(typeof(ObservableCollection<Prediction>));
            ObservableCollection<Prediction> data = (ObservableCollection<Prediction>)serializer.Deserialize(isoStream);
            this.list_locationAdd.ItemsSource = data;
        }
    }
    catch(Exception ex) 
    { }
}
else
{
    try
    {   
        using (IsolatedStorageFileStream isoStream = new IsolatedStorageFileStream(filename, FileMode.Create, isoStore))
        {
            XmlSerializer Serialize = new XmlSerializer(typeof(ObservableCollection<Prediction>));
            using (XmlWriter writer = XmlWriter.Create(isoStream, x_W_Settings))
            {
                data.Add(new Prediction() { description = App.professionalId });
                list_locationAdd.ItemsSource = data;
                Serialize.Serialize(writer, data);
            }
        }
    }
    catch (Exception ex)
    { }
}

希望这对你有所帮助。

使用硬件返回按钮后，Windows Phone 8无法更新XML文件中的列表框项目？

1 个答案: