将值从单选按钮组传递到另一个页面（Windows Phone）

Question

I have TestPage.xaml in which i run a test with questions. I have set maxCount=10 so when i have ten questions the test ends. I want to make a settingPage.xaml with 3 radio buttons 10 , 15 , 20 so when the user checks one of them to set the maxCount, it will store in IsolatedStorageSettings. But i can't figure out how to check in my TestPage.xaml which radiobutton is clicked, to know how many questions to load?

How can I achieve this without If-Else statements?

Answer 1

You can use a query string. When you navigate to TestPage.xaml pass in the max count value

NavigationService.Navigate(new Uri("/TestPage.xaml?maxcount=" + maxCount, UriKind.Relative));

In your TestPage.xaml page, override the OnNavigatedTo method and check the query string value passed.

protected override void OnNavigatedTo(NavigationEventArgs e)
{
   string maxCount = string.Empty;
   if (NavigationContext.QueryString.TryGetValue("maxcount", out maxCount))
   {
      //parse the int value from the string or whatever you need to do
   }
}

Alternatively, you say you've stored it in isolated storage so you could also just read it back from that. The query string method would be faster but the isolated storage method will let you read it back at a later time if the user has closed the app.

Update based on comment

You can store a file that contains the data in Isolated Storage (you should add error handling)

using(var fs = IsolatedStorageFile.GetUserStoreForApplication())
using(var isf = new IsolatedStorageFileStream("maxCount.txt", FileMode.OpenOrCreate, fs))
using(var sw = new StreamWriter(isf))
{
   sw.WriteLine(maxCount.ToString());      
}

Then read it back

using(var fs = IsolatedStorageFile.GetUserStoreForApplication())
using(var isf = new IsolatedStorageFileStream("maxCount.txt", FileMode.Open, fs))
using(var sr = new StreamReader(isf)
{
   string maxCount = sr.ReadToEnd();
   //you now have the maxCount value as string
   //... 
}

Answer 2

See draw back here with isolated storage is it will take up a memory space even when you are not running the app. So while the app is running why don't you go ahead and save your options in Application.Current.Resources for example :

Application.Current.Resources.Add("Maybe Question section", 50); //will load 50 questions for particular section.

and while fetching

Application.Current.Resources["Maybe Question section"]

and then tryParse it to integer and get the number. this will be application wide until the app is running . You can fetch every time for a particular section. No need to connect to the isolated storage again and again to fetch or keep modifying files.