计算点击次数并显示在另一页上[Windows Phone c＃]

Question

I am trying to count how many times button1 is clicked on page1, then display the amount of clicks on page2 in a textbox1.

I've tried to code below but it is giving me an exception error on the line ' String count= localSettings.Values["Count"].ToString(); '.

Is there another way to do what I want to?

Page 1

  private void button1_Click(object sender, RoutedEventArgs e)
    {
        var localSettings = Windows.Storage.ApplicationData.Current.LocalSettings;
        String count= localSettings.Values["Count"].ToString();
        int tc = int.Parse(count);
        tc++;
        localSettings.Values["Count"] = tc;

    }

Page 2

        var localSettings = Windows.Storage.ApplicationData.Current.LocalSettings;
        textbox1.Text = localSettings.Values["Count"].ToString();

Answer 1

When you access "Count" for the first time, it does not exist. localSettings.Values["Count"] is therefore going to be null. You then try to call ToString() on an object that is null and that causes the exception.

Try this:

private void button1_Click(object sender, RoutedEventArgs e)
{
    var localSettings = Windows.Storage.ApplicationData.Current.LocalSettings;
    int tc = 0;
    if( localSettings.Values["Count"] != null )
    {
        String count= localSettings.Values["Count"].ToString();
        tc = int.Parse(count);
    }
    tc++;
    localSettings.Values["Count"] = tc;

}