Question

在我的WP8应用程序中，我使用带有多选选项的ListPicker控件。在我的页面中，我正在从自定义类列表中加载Listpicker数据。我可以通过实现SummaryForSelectedItemsDelegate事件来保存用户选择的对象，并将此信息保存到隔离存储中以供以后访问。

我的主要问题是，当用户打开此列表选择器所在的页面时，如何选择上述用户选择的选项？

我尝试使用SelectionChanged事件并尝试根据存储的数据选择对象，但它没有用。

<toolkit:ListPicker x:Name="userCountryList" ItemsSource="{Binding CountryList}"  Header="Choose a country or region:"  SelectionMode="Multiple" FullModeItemTemplate="{StaticResource DataTemplate2}" />

<phone:PhoneApplicationPage.Resources>
<DataTemplate x:Key="DataTemplate2">
    <StackPanel Orientation="Horizontal">
       <TextBlock HorizontalAlignment="Left"  FontSize="28" TextWrapping="Wrap" Text="{Binding CountryName}" VerticalAlignment="Center" Width="Auto"/>
    </StackPanel>
</DataTemplate>

代码背后：

var brushes = new List<CustomClass>();
brushes.Add(new CustomClass { CountryCode = "US", CountryName = "United States" });
brushes.Add(new CustomClass { CountryCode = "FR", CountryName = "France" });
brushes.Add(new CustomClass { CountryCode = "DE", CountryName = "Germany" });
brushes.Add(new CustomClass { CountryCode = "CA", CountryName = "Canada" });

userCountryList.SummaryForSelectedItemsDelegate = SummarizeItems;
userCountryList.ItemsSource = brushes;


private string SummarizeItems(IList items)
    {
        if (items != null && items.Count > 0)
        {
            string summarizedString = "";

            if (items != null)
                for (int i = 0; i < items.Count; i++)
                {
                    summarizedString += ((CustomClass )items[i]).CountryCode;

                    // If not last item, add a comma to seperate them
                    if (i != items.Count - 1)
                        summarizedString += ", ";
                }

            if (!AppSettings.Default.UserSelectedMarkets.Equals(summarizedString))
                AppSettings.Default.UserSelectedMarkets = summarizedString;

            return summarizedString;
        }
        else
            return "Nothing selected";
    }

Answer 1

在您的页面中，覆盖OnNavigatedTo并将所有对象添加到userCountryList.SelectedItems：

protected override void OnNavigatedTo(NavigationEventArgs e)
{
    foreach (var o in GetSelectedObjects())
    {
        userCountryList.SelectedItems.Add(o);
    }
    base.OnNavigatedTo(e);
}

如何在SelectionMode为多个的位置设置Listpicker项

1 个答案: