// *** Private Methods ***
private async Task <LoadMoreItemsResult> LoadMoreItemsAsyncInternal(int count)
{
IsLoading = true;
// If we currently do not know the number of items then fetch this
if (sourceCount == null)
{
sourceCount = await dataListSource.GetCountAsync();
}
// Set a minimum paging size if requested
count = Math.Max(count, MinimumPagingSize);
// Limit the number of items to fetch to the number of remaining items
count = Math.Min(count, sourceCount.Value - currentCount);
// Get all the items and wait until they are all fetched
Task <T>[] fetchItemTasks = new Task <T> [count];
int startIndex = currentCount;
for (int i = 0; i < count; i++)
{
fetchItemTasks[i] = dataListSource.GetItemAsync(startIndex + i);
}
await Task.WhenAll(fetchItemTasks);
// Increment the current count
currentCount += count;
// Set properties and raise property changed for HasMoreItems if this is not false
IsLoading = false;
if (currentCount == sourceCount)
{
OnPropertyChanged("HasMoreItems");
}
// Raise collection changed events
OnItemsAdded(startIndex, count);
// Return the number of items added
return(new LoadMoreItemsResult()
{
Count = (uint)count
});
}
// *** Overridden Base Methods ***
protected override Task <int> GetCountAsync()
{
return(dataListSource.GetCountAsync());
}