Add async way to controller, make the UI response smoothly about autox HOT 2 CLOSED

replace line 130-148 of MainWindow.Table.xmal.cs with:
private async void TestCaseResultTableSelectionChanged(object sender, 
SelectionChangedEventArgs e)
        {
            if (TestCaseResultTable == null) return;
            var selected = TestCaseResultTable.SelectedItem as Result;
            if (selected == null) return;
            await UpdateResultTable(selected._id);
        }
private async Task UpdateResultTable(string id)
{
    _testStepSource.Clear();
    var xRoot = DBFactory.GetData().GetChildren(id);
            if (xRoot.HasElements)
            {                
                foreach (XElement kid in xRoot.Descendants())
                {
                    var testcaseresult = 
kid.GetDataObjectFromXElement() as StepResult;
                    if (testcaseresult != null)
                        _testStepSource.Add(testcaseresult);
                }
            }
            TestStepsResultTable.ItemsSource = _testStepSource.Get(); 
}