Question

我有一个水果应用程序的列表框。我希望列表框中的每个项目在被选中时，将您带到另一个页面，告诉用户更多关于水果的信息。我知道导航到一个页面的代码，但是我在使用switch case语句导航到几个页面时遇到了麻烦。这是代码：

MainPage.xaml中

<Grid x:Name="ContentPanel" Grid.Row="1" Margin="10,10,14,-10">
<phone:LongListSelector HorizontalAlignment="Left" Height="432" VerticalAlignment="Top" Width="446" Margin="7,129,0,0"/>
        <ListBox Margin="0,-12,0,52" Name="FruitListbox" SelectionChanged="fruitList_SelectionChanged" SelectionMode="Extended" ItemsSource="{Binding}">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <StackPanel Orientation="Horizontal" Height="230">
                        <Image Name="Image" Width="100" Height="250" Source="{Binding Image}" VerticalAlignment="Top" Margin= "0,0,10,0"></Image>
                        <StackPanel x:Name="lBtn" Width="370" HorizontalAlignment="Left" Height="350">
                            <TextBlock Text="{Binding Name}" Foreground="Red"></TextBlock>
                            <TextBlock Text="{Binding Description}" Foreground="Aqua"></TextBlock>
                        </StackPanel>
                    </StackPanel>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>
    </Grid>

MainPage.xaml.cs中

namespace Carifruits
{
 public partial class MainPage : PhoneApplicationPage
 {
    ObservableCollection<Fruit> fruitiness = new ObservableCollection<Fruit>();

public MainPage()
{

    InitializeComponent();
    Fruit fruit1 = new Fruit
    {
        Name = "Abricot",
        Description = "Classified with the Plum",
        Image = "http://img.xooimage.com/files68/5/1/1/abricot-gp14-1--30f6578.jpg",

    };
    Fruit fruit2 = new Fruit
    {
        Name = "Breadfruit",
        Description = "Species of flowering tree",
        Image = "http://nickandmiri.files.wordpress.com/2010/06/breadfruit2.jpg",



    };
    Fruit fruit3 = new Fruit
    {
        Name = "Coconut",
        Description = "Can refer to the entire Coconut Palm",
        Image = "http://www.internationalcoconut.com/coconuts.jpg",


    };
    Fruit fruit4 = new Fruit
    {
        Name = "Hog Plum",
        Description = "Yellowish plum, related to the Mango",
        Image = "http://streetsmartbrazil.com/userfiles/image/caj%C3%A1.jpg",


    };

    Fruit fruit5 = new Fruit
    {
        Name = "Padoo",
        Description = "Tree-growing bean pods ",
        Image = "http://caribfruits.cirad.fr/var/caribfruits/storage/images/fruits_des_antilles/pois_doux/2376-3-fre-FR/pois_doux.jpg",


    };

    fruitiness.Add(fruit1);
    fruitiness.Add(fruit2);
    fruitiness.Add(fruit3);
    fruitiness.Add(fruit4);
    fruitiness.Add(fruit5);

    LayoutRoot.DataContext = new CollectionViewSource { Source = fruitiness };

       }

public class Fruit
{

    public Fruit() { }

    public string Image { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }


}

private void fruitList_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
    {
        if (FruitListbox.SelectedIndex == -1) return;
        Fruit data = FruitListbox.SelectedItem as Fruit;

        switch (data.Description)
        {
            case "fruit1":
                NavigationService.Navigate(new Uri("/Pano.xaml?selectedItem=" + FruitListbox.SelectedIndex, UriKind.Relative));
                break;
            case "fruit2":
                NavigationService.Navigate(new Uri("/Pano2.xaml?selectedItem=" + FruitListbox.SelectedIndex, UriKind.Relative));
                break;
            case "fruit3":
                NavigationService.Navigate(new Uri("/Pano3.xaml?selectedItem=" + FruitListbox.SelectedIndex, UriKind.Relative));
                break;
            case "fruit4":
                NavigationService.Navigate(new Uri("/Pano4.xaml?selectedItem=" + FruitListbox.SelectedIndex, UriKind.Relative));
                break;
            case "fruit5":
                NavigationService.Navigate(new Uri("/Pano5.xaml?selectedItem=" + FruitListbox.SelectedIndex, UriKind.Relative));
                break;
            default:
                MessageBox.Show("Please Select From the list!");
                break;




        }


        FruitListbox.SelectedIndex = -1;
    }
}
}
}

有人可以帮忙吗？

Answer 1

你的switch语句会切换你的Fruit对象的描述，但是case的比较值是......究竟是什么？看起来他们是变量名。

通常，最好使用Enums或Integers进行切换。

在您的情况下，您可以尝试使用切换水果的名称，或改为data.Name。

    switch (data.Description)
    {
        case "Abricot":
            ...
            break;
        case "Breadfruit":
            ...
            break;
        case "Coconut":
            ...
            break;
        case "Hog Plum":
            ...
            break;
        case "Padoo":
            ...
            break;
        default:
            MessageBox.Show("Please Select From the list!");
            break;
    }

但是，更好的方法是使用水果列表中水果项的索引。

    switch (fruitiness.IndexOf(data))
    {
        case 0:
            ...
            break;
        case 1:
            ...
            break;
        case 2:
            ...
            break;
        case 3:
            ...
            break;
        case 4:
            ...
            break;
        default:
            MessageBox.Show("Please Select From the list!");
            break;
    }

当然，还有比这更好的方法。您可以完全避免使用开关。

 var navigateUrlIndex = fruitiness.IndexOf(data) + 1;
 var navigateUrl = String.Format("/Pano{0}.xaml?selectedItem={1}", navigateUrlIndex != 1 ? "" : navigateUrlIndex, FruitListbox.SelectedIndex);

 if (FruitListbox.SelectedIndex != -1) {
     NavigationService.Navigate(new Uri(navigateUrl, UriKind.Relative));
 }

这样的事情应该指向正确的方向。（未经测试）

列表框中的每个项目都可导航到其他页面

1 个答案: