paging and clearing filters

[David Ocasio]

I have what i beleive to be a bug (2012.2.607.1050 version)
although it could be the way i am doing it

I needed a button that would clear all the filters that have been set up on a radgridview that was
fed by a domaindatasource/pager

I used code that was posted by the admin Ross for clearing the filters

Private Sub btnClear_Click(sender As Object, e As System.Windows.RoutedEventArgs) Handles btnClear.Click
    radGridView.FilterDescriptors.SuspendNotifications()
    For Each column In radGridView.Columns
        If column.FilteringControl IsNot Nothing Then
        Else
            column.ClearFilters()
        End If
    Next
    radGridView.FilterDescriptors.ResumeNotifications()
End Sub

What i found was some unusal behavior where multiple loads were being started on the DDS.

In an effort to demonstarte this behavior i authored a short demo/test against the northwind database
I removed the domaindatasource and replaced it with a QueryableDomainServiceCollectionView

if you filter a number of columns
Then change the page to 2 or 3 or any page except the first one
Press the clear button.

Multiple loads will be started and completed
See code and Debug Output below

is there somehting i am doing wrong
is there a better way
is it a bug (i think so)

thanks
dco

<UserControl x:Class="agTesty6.MainPage"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:telerik="http://schemas.telerik.com/2008/xaml/presentation"
        mc:Ignorable="d" d:DesignWidth="640" d:DesignHeight="480">

    <Grid x:Name="LayoutRoot">
        <Grid.RowDefinitions>
            <RowDefinition Height="*" />
            <RowDefinition Height="Auto" />
            <RowDefinition Height="Auto" />
        </Grid.RowDefinitions>

        <telerik:RadGridView x:Name="radGridView"
                             Grid.Row="0"
                             ItemsSource="{Binding DataView}"
                             ShowGroupPanel="False"
                             AutoGeneratingColumn="OnRadGridViewAutoGeneratingColumn"
                             IsReadOnly="True"/>

        <telerik:RadDataPager x:Name="radDataPager"
                              PageSize="10"
                              Grid.Row="1"
                              AutoEllipsisMode="Both"
                              NumericButtonCount="10"
                              Source="{Binding DataView}"
                              DisplayMode="All"
                              IsTotalItemCountFixed="True"/>
        <Button Content="Clear" Grid.Row="2" Margin="4" Width="75" HorizontalAlignment="Right" x:Name="btnClear"  />
    </Grid>
</UserControl>

Imports System
Imports System.Linq
Imports System.Windows.Controls
Imports Telerik.Windows.Controls.DomainServices
Imports Telerik.Windows.Data
Partial Public Class MainPage
    Inherits UserControl

    Public Sub New()
        InitializeComponent()

        Dim domainContext As New agTesty6.Web.NorthWindDomainContext

        Dim query = domainContext.GetCustomers_OrderedQuery
        _DataView = New QueryableDomainServiceCollectionView(Of agTesty6.Web.Customer)(domainContext, query)

        Me.DataContext = Me
        _DataView.AutoLoad = True

    End Sub

    Public ReadOnly Property DataView() As QueryableCollectionView
        Get
            Return _DataView
        End Get
    End Property
    Private WithEvents _DataView As QueryableDomainServiceCollectionView(Of agTesty6.Web.Customer)

    Private Sub OnRadGridViewAutoGeneratingColumn(sender As System.Object, e As Telerik.Windows.Controls.GridViewAutoGeneratingColumnEventArgs)
    End Sub

    Private Sub btnClear_Click(sender As Object, e As System.Windows.RoutedEventArgs) Handles btnClear.Click
        radGridView.FilterDescriptors.SuspendNotifications()
        For Each column In radGridView.Columns
            If column.FilteringControl IsNot Nothing Then
            Else
                column.ClearFilters()
            End If
        Next
        radGridView.FilterDescriptors.ResumeNotifications()
    End Sub

    Private Sub _DataView_LoadedData(sender As Object, e As Telerik.Windows.Controls.DomainServices.LoadedDataEventArgs) Handles _DataView.LoadedData
        System.Diagnostics.Debug.WriteLine("Dataview Loaded Data -- " & e.Entities.Count)
    End Sub

    Private Sub _DataView_LoadingData(sender As Object, e As Telerik.Windows.Controls.DomainServices.LoadingDataEventArgs) Handles _DataView.LoadingData
        System.Diagnostics.Debug.WriteLine("======================")
        System.Diagnostics.Debug.WriteLine("Dataview Loading Data")
        System.Diagnostics.Debug.WriteLine(e.Query.Query)
    End Sub
End Class

======================
Dataview Loading Data
agTesty6.Web.Customer[].Where(item => item.CompanyName.ToLower().Contains("s".ToLower())).Skip(30).Take(10)
Dataview Loaded Data -- 10
======================
Dataview Loading Data
agTesty6.Web.Customer[].Take(10)
======================
Dataview Loading Data
agTesty6.Web.Customer[].Take(10)
======================
Dataview Loading Data
agTesty6.Web.Customer[].Skip(30).Take(10)
Dataview Loaded Data -- 10
Dataview Loaded Data -- 10
Dataview Loaded Data -- 10

[Rossen Hristov]

Hello,

Do you have this sample project targeting Northwind? Can you send it to me for debugging?

Regards,
Ross
the Telerik team

[David Ocasio]

Ok 
I opened support ticket 561359
So i could upload the demo solution for your review.
I referenced this forum as well as your name in the ticket.

thanks ross
dco

[Rossen Hristov]

Hi,

Can you please add this code to your source code:

Private Sub btnClear_Click(sender As Object, e As System.Windows.RoutedEventArgs) Handles btnClear.Click
    Using (_DataView.DeferRefresh())
        radGridView.FilterDescriptors.SuspendNotifications()
        For Each column In radGridView.Columns
            If column.FilteringControl IsNot Nothing Then
            Else
                column.ClearFilters()
            End If
        Next
        radGridView.FilterDescriptors.ResumeNotifications()
    End Using
End Sub

When the QDSCV is on a page different from the first one, it will try to move back to page 0 after a dramatic change occurs, i.e. filtering, that is why it may load a couple of times. If you surround the de-filtering in a DeferRefresh call all should happen in a single batch operation.

I hope this helps.

Regards,
Ross
the Telerik team

[David Ocasio]

Thanks ross

That does work

Had to refactor a little since my production code has a radomaindatasource as opposed to the QueryableDomainServiceCollectionView
I used in the example and the "DeferRefresh" is not exposed.

But it does work as you said.

thanks
dco