/// <param name="fetchDataCallback">Callback used when more data is requested for the cache</param>
/// <param name="updateCountCallback">Callback used to calculate the total number of items that exist outside the cache</param>
/// <param name="cacheBatchSize">Cache batch size</param>
public VirtualizedDataSource(FetchDataCallbackHandler <T> fetchDataCallback, UpdateCountCallbackHandler updateCountCallback, int cacheBatchSize = 10)
{
// The ItemCacheManager does most of the heavy lifting. We pass it a callback that it will use to actually fetch data, and the max size of a request
_itemCache = new ItemCacheManager <T>(fetchDataCallback, cacheBatchSize);
_itemCache.CacheChanged += ItemCache_CacheChanged;
_updateCountCallback = updateCountCallback;
UpdateCount();
}
public ENRZDataContext(FetchDataCallbackHandler back, int num, uint rollNum, string targetHost)
{
FetchCallback = back;
number = num;
rollNumber = rollNum;
this.targetHost = targetHost;
InitType = InitSelector.Default;
}
public IncrementalLoadingContext(FetchDataCallbackHandler callback, int typeNumber, uint rollNumber, string targetHost)
{
FetchCallback = callback;
number = typeNumber;
this.rollNumber = rollNumber;
this.targetHost = targetHost;
InitType = InitSelector.Default;
}
public DoubanIncrementalContext(FetchDataCallbackHandler callback, int offset = 0, InitSelector type = InitSelector.Default)
{
FetchCallback = callback;
this.offset = offset;
InitType = type;
if (InitType == InitSelector.Special)
{
LoadPreviewAsync();
}
}
public ENRZDataContext(FetchDataCallbackHandler back, uint rollNum, string targetHost, InitSelector type)
{
FetchCallback = back;
number = 0;
rollNumber = rollNum;
this.targetHost = targetHost;
InitType = type;
if (InitType == InitSelector.Special)
{
LoadPreview();
}
}
public IncrementalLoadingContext(FetchDataCallbackHandler callback, uint rollNumber, string targetHost, InitSelector type)
{
FetchCallback = callback;
number = 0;
this.rollNumber = rollNumber;
this.targetHost = targetHost;
InitType = type;
if (InitType == InitSelector.Special)
{
LoadPreview();
}
}
public ItemCacheManager(FetchDataCallbackHandler <T> callback, int batchsize = 50)
{
_cacheBlocks = new List <CacheEntryBlock <T> >();
_request = new ItemIndexRangeList();
_cachedResults = new ItemIndexRangeList();
_fetchDataCallback = callback;
_maxBatchFetchSize = batchsize;
// set up a timer that is used to delay fetching data so that we can catch up if the list is scrolling fast
_timer = new DispatcherTimer();
_timer.Tick += (sender, args) => { FetchData(); };
_timer.Interval = new TimeSpan(20 * 10000);
}
public DoubanLazyLoadContext(FetchDataCallbackHandler callback)
{
FetchCallback = callback;
}
