Silverlight ListBox SelectedItem binded：页面导航，获取项目，在新视图中显示其属性，并重置SelectedIndex。我该怎么办？

我正试图用MVVM Light在我的应用程序中应用MVVM模式。我有一个数据索引列表框

MainView.xaml[摘录]

<ListBox Name="recipesListBox" 
                             ItemsSource="{Binding RecipeList}"
                             SelectedItem="{Binding SelectedRecipe, Mode=TwoWay}"
                             HorizontalAlignment="Stretch"
                             VerticalAlignment="Stretch"
                             Grid.Row="1"
                             Margin="12,0,12,0"
                             SelectionChanged="recipesListBox_SelectionChanged" >

    private Recipe selectedRecipe;

    public Recipe SelectedRecipe
    {
        get
        {
            return selectedRecipe;
        }
        set
        {
            selectedRecipe = value;
            RaisePropertyChanged("SelectedRecipe");
        }
    }

private void recipesListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            string destination = "/RecipeView.xaml";
            if (recipesListBox.SelectedIndex == -1) // If selected index is -1 (no selection) do nothing
                return;
            this.NavigationService.Navigate(new Uri(destination, UriKind.Relative));
            //recipesListBox.SelectedIndex = -1; // Reset selected index to -1 (no selection)
        }

…对SelectionChanged执行页面导航：

MainView.xaml.cs[摘录]

<ListBox Name="recipesListBox" 
                             ItemsSource="{Binding RecipeList}"
                             SelectedItem="{Binding SelectedRecipe, Mode=TwoWay}"
                             HorizontalAlignment="Stretch"
                             VerticalAlignment="Stretch"
                             Grid.Row="1"
                             Margin="12,0,12,0"
                             SelectionChanged="recipesListBox_SelectionChanged" >

    private Recipe selectedRecipe;

    public Recipe SelectedRecipe
    {
        get
        {
            return selectedRecipe;
        }
        set
        {
            selectedRecipe = value;
            RaisePropertyChanged("SelectedRecipe");
        }
    }

private void recipesListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            string destination = "/RecipeView.xaml";
            if (recipesListBox.SelectedIndex == -1) // If selected index is -1 (no selection) do nothing
                return;
            this.NavigationService.Navigate(new Uri(destination, UriKind.Relative));
            //recipesListBox.SelectedIndex = -1; // Reset selected index to -1 (no selection)
        }

---

在//之后，您可以看到在页面导航之后重置索引的旧代码-现在，使用绑定数据，显然它还将null设置为my selected item！返回时，如何导航到新视图、显示选定项的属性并重置选定索引？谢谢大家!

最好的方法是将您的收藏存储在您可以随时随地访问它的地方（如在Windows Phone Databound应用程序项目中），并在导航uri中传递所选项目的索引

int index = recipesListBox.SelectedIndex;
this.NavigationService.Navigate(new Uri(destination +"?index="+index , UriKind.Relative));

然后在新页面的OnNavigatedTo方法中，从查询中获取索引并获取项目

override OnNavigatedTo(
{
    string index;
    if(NavigationContext.QueryString.TryGetValue("index", index))
    {
        // get the item from your collection based on this index
    }

}

---

我是这样做的：

protected override void OnNavigatedFrom(System.Windows.Navigation.NavigationEventArgs e)
{
    if (listBox.SelectedItem != null)
    {
        listBox.SelectedIndex = -1;
    }

    base.OnNavigatedFrom(e);
}

然后将以下内容添加到SelectionChanged事件

if(SelectedItem != null)
{
    // Do something with SelectedItem
}

---

谢谢你的回答！我以前的代码是这样的：Recipe selectedRecipe=Recipes ListBox.SelectedItem作为Recipe；this.NavigationService.Navigate（新Uri（destination+“？RecipeID=“+selectedRecipe.ID，UriKind.Relative））；this.recipesListBox.SelectedIndex=-1。。。在OnNavigatedTo中，我通过ID在xml“数据库”上使用LINQ查询检索了配方，只要我在方法中执行操作，所有操作都正常工作，但在方法之外，配方显示为空！很明显，我保存了“外部”配方，但它总是显示为空！通常在OnNavigatedTo中，在outside中为null：（您是说查询字符串“RecipeID”不可用且为空？应保留在NavigationContext中。或者您是说配方本身为空？或者配方集合为空？在哪个页面中为空？配方本身为空！我在新视图中的代码如下：private Recipe selectedRecipe；override on NavigatedTo（{string ID；if（NavigationContext.QueryString.TryGetValue（“ID”，ID））{this.selectedRecipe=GetRecipeByID（ID）；}}}即，如果我尝试获取名称（selectedRecipe.Name）在OnNavigatedTo内部，我得到了我想要的东西，如果我在外部尝试，我得到了NullsomethingException！感谢您的回答！我昨天自己找到了解决方案，我完全按照您的方式编写了代码！除了if（）和base。OnNavigatedFrom（e），我现在正在添加它XD再次感谢您