c# - Passing a string between pages in Windows Phone 8

Question

I need to pass a simple string between two pages in Windows Phone 8. I've been searching around, trying to find the best way of doing it - but the ones i tried turned out to not work as they should - so i ask you: What is the best way to pass a simple string between two pages in Windows Phone 8. This is the method I use to navigate to the other page:

NavigationService.Navigate(new Uri("/newpage.xaml", Urikind.Relative));

Answer 1

For a string variable, it's easiest to use a query string parameter:

NavigationService.Navigate(new Uri("/newpage.xaml?key=value", Urikind.Relative));

Pick it up on the target page using NavigationContext.QueryString:

protected override void OnNavigatedTo(NavigationEventArgs e)
{
    if (NavigationContext.QueryString.ContainsKey("key"))
    {
         string val = NavigationContext.QueryString["key"];
         // etc ...
    }
}

---

Note: if your string contains only alphanumeric characters, then the above will work without modification. But, if your string might have URL-reserved characters (eg, &, ?), then you'll have to URL-encode them. Use the helper methods Uri.EscapeDataString and Uri.UnescapeDataString for this.

To escape:

string encodedValue = Uri.EscapeDataString("R&R");
NavigationService.Navigate(new Uri("/newpage.xaml?key=" + encodedValue, Urikind.Relative));

To unescape:

string encodedValue = NavigationContext.QueryString["key"];
string val = Uri.UnescapeDataString(encodedValue);