public async Task <DateTime> LoadDataAsync(ObservableCollection <T> viewItems, bool forceRefresh)
{
DateTime timeStamp = DateTime.Now;
if (HasStaticData)
{
viewItems.AddRangeUnique(await LoadDataAsync());
}
else
{
var dataInCache = await AppCache.GetItemsAsync <T>(CacheKey);
if (dataInCache != null)
{
timeStamp = dataInCache.TimeStamp;
viewItems.AddRangeUnique(dataInCache.Items);
}
if (NetworkInterface.GetIsNetworkAvailable() && DataNeedToBeUpdated(forceRefresh, dataInCache))
{
var freshData = await UpdateCache();
viewItems.AddRangeUnique(freshData.Items);
timeStamp = freshData.TimeStamp;
}
}
return(timeStamp);
}
internal async Task <DataSourceContent <T> > UpdateCache()
{
var freshData = new DataSourceContent <T>()
{
TimeStamp = DateTime.Now,
Items = await LoadDataAsync()
};
await AppCache.AddItemsAsync(CacheKey, freshData);
return(freshData);
}