/// <summary>
/// Execute given query and show all entities in the result.
/// </summary>
/// <param name="query">Query to show</param>
public async Task LoadQueryAsync(IExecutableQuery query)
{
// release all resources used by the previous query
DisposeQuery();
_selection.Clear();
// start the query
_queryEvaluator = _queryEvaluatorFactory.Create(query);
View.Query = _queryEvaluator.Query.Text;
View.Items = _queryEvaluator.Update();
View.History.CanGoBackInHistory = _queryHistory.Previous != null;
View.History.CanGoForwardInHistory = _queryHistory.Next != null;
View.BeginLoading();
View.BeginPolling(PollingRate);
try
{
await _queryEvaluator.RunAsync();
if (!_isDisposed)
{
View.UpdateItems();
}
}
catch (OperationCanceledException)
{
}
finally
{
if (!_isDisposed)
{
View.EndLoading();
}
}
}
/// <summary>
/// Dispose all resources used by current query
/// </summary>
private void DisposeQuery()
{
_queryEvaluator?.Dispose();
_queryEvaluator = null;
View.Items = null; // the items have been disposed by the query evaluator
}