填充ListView之后，设置它的SelectedIndex属性

Question

I want to set the SelectedIndex property of a ListView to the value which was selected before the termination of the app.

So, just before the app is suspended, I save the SelectedIndex value.

Now in the OnLaunched() method, when I set the SelectedIndex property to that value, I get the ArgumentException, which says value not within the expected range. I searched for it, and found that the SelectedIndex property of the ListView was being changed before being populated (so the only valid value of the SelectedIndex is -1 at that time).

Ok, fine. But how to set the SelectedIndex property after the ListView is populated?

What is the easiest way? Should I dive into ItemsChanged events?

Update: Here's the code:

public sealed partial class MyPage : Page
{
    public List<String> myList { get; set; }

    public MyPage()
    {
        this.InitializeComponent();

        myList = new List<string>()
        {
            "hello",
            "this",
            "is",
            "me"
        };                        //This is the ItemSource for the ListView
        ...
    }

    public void SetUpUI(int selectedItem)    //This method is called from
    {                                        //the OnLaunched() method
        MyListView.SelectedIndex = selectedItem;
    }
    ...
}

Answer 1

使用Page.Load或Page.LoadComplete事件设置您选择的项目。

Answer 2

Solved this by using the Loaded event of this page, like so:

public sealed partial class MyPage : Page
{
    public List<String> myList { get; set; }
    int selectedItem = -1;

    public MyPage()
    {
        this.InitializeComponent();

        myList = new List<string>()
        {
            "hello",
            "this",
            "is",
            "me"
        };

        Application.Current.Suspending += App_Suspending;

        this.Loaded += MyPage_Loaded;
    }

    private void MyPage_Loaded(object sender, RoutedEventArgs e)
    {
        MyListView.SelectedIndex = selectedItem;
    }

    ...

    public void SetUpUI(int prevSelectedIndex)
    {
        selectedItem = prevSelectedIndex;
    }
}