Setting DataLoadMode="Asynchronous" still blocks the UI thread

[Tor]

We have implemented a search as you type control using the RadGridView. Everytime the text changes we set the ItemsSource to a new source and when data is being loaded the text box is unresponsive. We have specified DataLoadMode="Asynchronous" but it doesn't help. Any ideas?

[Vlad]

Hello,

 Why not use the grid filtering instead similar to our demo? When you reset ItemsSource the entire UI will be recreated from scratch which is expensive operation.  

Greetings,
Vlad
the Telerik team

[Tor]

Because that filtering does not work well with the NHibernate Linq provider. At the moment our code looks like this:

Private Sub UpdateQuery()
    If String.IsNullOrEmpty(SearchText) Then
        GridView.ItemsSource = CreateCollectionView(ItemsSource)
        Return
    End If

    Dim query = ItemsSource
    Dim dynamicQuery = String.Empty
    Dim exactMatchesQuery = String.Empty
    Dim excludeQuery = String.Empty

    For Each path In FilterPaths
        dynamicQuery &= path & ".StartsWith(""" & SearchText & """) Or "
        exactMatchesQuery &= path & ".Equals(""" & SearchText & """) Or "
        excludeQuery &= "(" & path & " <> NULL And " & path & ".Equals(""" & SearchText & """)) Or "
    Next

    dynamicQuery = dynamicQuery.Substring(0, dynamicQuery.Length - 4)
    exactMatchesQuery = exactMatchesQuery.Substring(0, exactMatchesQuery.Length - 4)
    excludeQuery = excludeQuery.Substring(0, excludeQuery.Length - 4)

    Dim fullQuery = "(" & dynamicQuery & ")" & " And Not (" & excludeQuery & ")"
    Dim exactMatches = ItemsSource.Where(exactMatchesQuery).ToIList()
    Dim collectionView = CreateCollectionView(query.Where(fullQuery))

    GridView.ItemsSource = collectionView

    Dispatcher.BeginInvoke(
        Sub()
            For Each match In exactMatches
                collectionView.Insert(0, match)
            Next

            collectionView.MoveCurrentToFirst()
        End Sub, DispatcherPriority.Input)
End Sub

Not optimal but it is the only working filtering against NHibernate's IQueryable.

[Vlad]

Hi Tor,

 We've fixed this (DataLoadMode="Asynchronous" on initial load) and the fix will be part of our next internal build. I've added 2000 Telerik points to your account. 

All the best,
Vlad
the Telerik team