问如何在应用程序运行期间始终保持页面状态？(WP8)

EN

> >>OnNavigatedToMethod_AnyPage
> -->Check if cache exists in isolated storage
> --->If it does get the cache and load the values into the page
> ---> if it doesnt exist create a new one and save default values
> 
> >>OnNavigatedFromMethod_AnyPage
> -->Load values into cache object
> --->Save cache object to isolated storage

[DataContractAttribute]//This tells the EZ_Iso dll that this object is serializable 
public PageOneCache{

    [DataMember] //This tells the serializer to serialize this member
    public bool flag1 {get; set;}

    [DataMember]
    public List<int> ages {get;set;}

    public int boxes {get; set;} // This member doesn't have the [DataMember] so it wont get saved
}

PageOneCache pageOneCache = new PageOneCache(){ flag1 = true, ages = new List<int>(){1,3,4}, boxes = 2};

if(EZ_iso.IsolatedStorageAccess.FileExists("pageOneCache")
   Ez_iso.IsolatedStorageAccess.OverwriteFile("pageOneCache",pageOneCache);
else
   Ez_iso.IsolatedStorageAccess.SaveFile("pageOneCache",pageOneCache);

PageOneCache pageOneCache = (PageOneCache)EZ_iso.IsolatedStorageAccess.GetFile("pageOneCache",typeof(PageOneCache));