Windows Phone Dev c#:在页面之间发送信息

我试图在两个页面之间发送几个字符串。然而，接收页面只将其解释为一个。有什么建议吗?

第1页

private void button1_Click(object sender, RoutedEventArgs e)
        {
            string urlofdestinationpage = "/Page1.xaml";
            urlofdestinationpage += string.Format("?SelectedIndex=" + playersList.SelectedIndex);
            urlofdestinationpage += string.Format("?Player1=" + textBox1.Text);
            NavigationService.Navigate(new Uri(urlofdestinationpage, UriKind.Relative));
        }

第2页

protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
        {
            IDictionary<string, string> x = this.NavigationContext.QueryString;
            String size = Convert.ToString(x["SelectedIndex"]);
            MessageBox.Show(size);
String player = Convert.ToString(x["Player1"]);
                MessageBox.Show(player1);
            base.OnNavigatedTo(e);
        }

接收页输出消息"0?"Player1="并且不识别Player1作为值。

帮忙吗?

private void button1_Click(object sender, RoutedEventArgs e)
{
    string urlofdestinationpage = "/Page1.xaml";
    urlofdestinationpage += string.Format("?SelectedIndex=" + playersList.SelectedIndex);
    urlofdestinationpage += string.Format("&Player1=" + textBox1.Text);
    NavigationService.Navigate(new Uri(urlofdestinationpage, UriKind.Relative));
}