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On RadGrid CustomPaging and FilteringByColumn working together

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This is a migrated thread and some comments may be shown as answers.

Lorenzo asked on 27 Jul 2012, 09:05 AM

Hi,
I'm looking for a very urgent clarification about the concurrency of CustomPaging and FilteringByColumn used together in a RadGrid.
I always have as a datasource a function that returns a DataTable considering both Filtering and Paging. This is necessary since the amount of datas is very significative and cannot return the whole amount of datas to the RadGrid and the Page it, but I have to return only the needed records and only in small paged size (50 records).

The approach I've used up to now is as illustrated here:
Default.aspx

<%@ Page Language="VB" AutoEventWireup="false" CodeFile="Default.aspx.vb" Inherits="_Default" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">

<head runat="server">

<title></title>

<telerik:RadStyleSheetManager id="RadStyleSheetManager1" runat="server" />

</head>

<body>

<form id="form1" runat="server">

<telerik:RadScriptManager ID="RadScriptManager1" runat="server">

<Scripts>

<%--Needed for JavaScript IntelliSense in VS2010--%>

<%--For VS2008 replace RadScriptManager with ScriptManager--%>

<asp:ScriptReference Assembly="Telerik.Web.UI" Name="Telerik.Web.UI.Common.Core.js" />

<asp:ScriptReference Assembly="Telerik.Web.UI" Name="Telerik.Web.UI.Common.jQuery.js" />

<asp:ScriptReference Assembly="Telerik.Web.UI" Name="Telerik.Web.UI.Common.jQueryInclude.js" />

</Scripts>

</telerik:RadScriptManager>

<script type="text/javascript">

//Put your JavaScript code here.

</script>

<telerik:RadAjaxManager ID="RadAjaxManager1" runat="server">

</telerik:RadAjaxManager>

<div>

<telerik:RadGrid runat="server" ID="RadGrid" AutoGenerateColumns="false" AllowCustomPaging="true" AllowPaging="true" PageSize="50"

AllowFilteringByColumn="true" EnableLinqExpressions="false">

<GroupingSettings CaseSensitive="False" />

<ClientSettings>

<Selecting AllowRowSelect="True" />

<Scrolling AllowScroll="True" ScrollHeight="100%" UseStaticHeaders="True" />

</ClientSettings>

<PagerStyle AlwaysVisible="True" />

<MasterTableView OverrideDataSourceControlSorting="True">

<NoRecordsTemplate>

</NoRecordsTemplate>

<Columns>

<%--Some columns here--%>

</Columns>

</MasterTableView>

</telerik:RadGrid>

</div>

</form>

</body>

</html>

Default.aspx.vb

Imports Telerik.Web.UI

Imports System.Data

Partial Class _Default

Inherits System.Web.UI.Page

Protected Sub RadGrid_NeedDataSource(ByVal sender As Object, ByVal e As Telerik.Web.UI.GridNeedDataSourceEventArgs) Handles RadGrid.NeedDataSource

Dim VirtualItemCount As Integer = GetDatasVirtualItemsCount(RadGrid.MasterTableView.FilterExpression)

RadGrid.MasterTableView.VirtualItemCount = VirtualItemCount

RadGrid.VirtualItemCount = VirtualItemCount

Dim startIndex As Integer = IIf((ShouldApplySortFilterOrGroup()), 0, RadGrid.CurrentPageIndex * RadGrid.PageSize)

Dim pageSize As Integer = IIf((ShouldApplySortFilterOrGroup()), VirtualItemCount, RadGrid.PageSize)

RadGrid.DataSource = GetDatas(startIndex, pageSize, RadGrid.MasterTableView.FilterExpression)

End Sub

Private isGrouping As Boolean = False

Protected Sub RadGrid1_GroupsChanging(ByVal source As Object, ByVal e As GridGroupsChangingEventArgs)

isGrouping = True

If e.Action = GridGroupsChangingAction.Ungroup AndAlso RadGrid.CurrentPageIndex > 0 Then

isGrouping = False

End If

End Sub

Public Function ShouldApplySortFilterOrGroup() As Boolean

Return RadGrid.MasterTableView.FilterExpression <> "" _

OrElse (RadGrid.MasterTableView.GroupByExpressions.Count > 0 OrElse isGrouping) OrElse RadGrid.MasterTableView.SortExpressions.Count > 0

End Function

Private Function GetDatas(ByVal startIndex As Integer, ByVal pageSize As Integer, ByVal FilterExpression As String) As DataTable

' ------------

' Some Code that generates a datatable considering both CustomPaging and Filtering

' ------------

Return New DataTable

End Function

Private Function GetDatasVirtualItemsCount(ByVal FilterExpression As String) As Integer

' ------------

' Some Code that count the number of rows considering Filtering

' ------------

Return -1

End Function

End Class

This works fine, but if I use Filtering then Paging gets disabled ! Now I need to use both together so my approach in the code behind has simply changed this way:

Imports Telerik.Web.UI

Imports System.Data

Partial Class _Default2

Inherits System.Web.UI.Page

Protected Sub RadGrid_NeedDataSource(ByVal sender As Object, ByVal e As Telerik.Web.UI.GridNeedDataSourceEventArgs) Handles RadGrid.NeedDataSource

Dim VirtualItemCount As Integer = GetDatasVirtualItemsCount(RadGrid.MasterTableView.FilterExpression)

RadGrid.MasterTableView.VirtualItemCount = VirtualItemCount

RadGrid.VirtualItemCount = VirtualItemCount

Dim startIndex As Integer = RadGrid.CurrentPageIndex * RadGrid.PageSize

Dim pageSize As Integer = RadGrid.PageSize

RadGrid.DataSource = GetDatas(startIndex, pageSize, RadGrid.MasterTableView.FilterExpression)

End Sub

Private Function GetDatas(ByVal startIndex As Integer, ByVal pageSize As Integer, ByVal FilterExpression As String) As DataTable

' ------------

' Some Code that generates a datatable considering both CustomPaging and Filtering

' ------------

Return New DataTable

End Function

Private Function GetDatasVirtualItemsCount(ByVal FilterExpression As String) As Integer

' ------------

' Some Code that count the number of rows considering Filtering

' ------------

Return -1

End Function

End Class

The only thing changed is the approach in retrieving the startIndex and the pageSize that now works the same way either if I'm filtering or not.

My point is: this thing seems to work, but I have to deliver it very soon and since I have not found posts of this approach anywhere I'm wondering if I'm missing something important that this approach does not consider.

If anybody finds reasonable reasons why this should fail in some circumstances please let me know.

Thanks in advance.

Lorenzo

On RadGrid CustomPaging and FilteringByColumn working together

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