AlternationCount problem ?

[Marjeta Segrec]

Hello.

I am using RowLoaded event for custom implementation - there is NO problem but problem occure if I set AlternationCount = 2. After that if you scrolling up/down the row.cells are duplicated and also Alternation style is not correct. I am prepared a simple sample where can you see the problem. If AlternationCount = 0 there is NO problem.

Option Strict On

Imports System.Collections
Imports System.Collections.Generic
Imports System.Collections.ObjectModel
Imports System.Globalization
Imports System.Linq
Imports System.Net
Imports System.ServiceModel
Imports System.Windows
Imports System.Windows.Data
Imports System.Windows.Media
Imports System.Windows.Resources
Imports System.Xml.Linq
Imports Telerik.Windows
Imports Telerik.Windows.Controls
Imports Telerik.Windows.Controls.GridView

Partial Public Class MainPage
    Inherits UserControl

    Public Sub New()
        InitializeComponent()

        If System.ComponentModel.DesignerProperties.GetIsInDesignMode(Me) Then
            Return
        End If ' System.ComponentModel.DesignerProperties.GetIsInDesignMode(Me)
        '
        AddHandler Me.Loaded, AddressOf OnMainPageLoaded
        AddHandler Me.RadGrid.RowLoaded, AddressOf OnRadGridRowLoaded
        '
        Me.RadGrid.AutoGenerateColumns = False
        Me.SetGrid()
        Me.LoadData()
    End Sub ' New()

    Private _DataSource As ObservableCollection(Of SampleData)
    Private ReadOnly Property DataSource() As ObservableCollection(Of SampleData)
        Get
            Return Me._DataSource
        End Get
    End Property ' DataSource()

    Private Sub LoadData()
        Me._DataSource = New ObservableCollection(Of SampleData)
        For a As Integer = 0 To 29
            Me.DataSource.Add(New SampleData(a + 1, String.Concat("Telerik.Windows.Controls.GridView (2009.3.1127.1030) - ", a + 1)))
        Next ' a As Integer = 0 To 29
        '
        Me.RadGrid.ItemsSource = Me.DataSource
    End Sub ' LoadData()

    Private Sub OnRadGridRowLoaded( _
        ByVal sender As Object, ByVal e As Telerik.Windows.Controls.GridView.RowLoadedEventArgs)

        Debug.WriteLine("OnRadGridRowLoaded - e.Row.Cells.Count = " & e.Row.Cells.Count)

    End Sub ' OnRadGridRowLoaded(ByVal sender As Object, ByVal e As ...GridView.RowLoadedEventArgs)

    Private Sub SetGrid()

        Me.RadGrid.AlternationCount = 2
        ' sample result :
        'OnRadGridRowLoaded(-e.Row.Cells.Count = 2)
        'OnRadGridRowLoaded(-e.Row.Cells.Count = 4)
        'OnRadGridRowLoaded(-e.Row.Cells.Count = 2)
        'OnRadGridRowLoaded(-e.Row.Cells.Count = 4)
        'OnRadGridRowLoaded(-e.Row.Cells.Count = 4)
        'OnRadGridRowLoaded(-e.Row.Cells.Count = 2)
        'etc...


        Me.RadGrid.CanUserFreezeColumns = False
        Me.RadGrid.CanUserReorderColumns = False
        Me.RadGrid.RowIndicatorVisibility = Windows.Visibility.Collapsed
    End Sub ' SetGrid()

    Private Sub OnMainPageLoaded(ByVal sender As Object, ByVal e As System.Windows.RoutedEventArgs)
        Me.SetGrid()
    End Sub ' OnMainPageLoaded(ByVal sender As Object, ByVal e As System.Windows.RoutedEventArgs)

End Class ' MainPage

Public Class SampleData
    Private _ID As Integer = 0
    Private _Name As String = String.Empty

    Public Sub New(ByVal [id] As Integer, ByVal [name] As String)
        Me.ID = [id]
        Me.Name = [name]
    End Sub ' New(ByVal [id] As Integer, ByVal [name] As String)

    Public Property ID() As Integer
        Get
            Return Me._ID
        End Get
        Set(ByVal value As Integer)
            Me._ID = value
        End Set
    End Property ' ID()

    Public Property Name() As String
        Get
            Return Me._Name
        End Get
        Set(ByVal value As String)
            Me._Name = value
        End Set
    End Property ' Name()

End Class ' SampleData

<UserControl x:Class="SilverlightRadGridTest.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:radgrid="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls.GridView"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d" d:DesignWidth="640" d:DesignHeight="480">

  <Grid x:Name="LayoutRoot">
        <Border Margin="10" Padding="4">
            <radgrid:RadGridView x:Name="RadGrid" AutoGenerateColumns="False" ColumnsWidthMode="Fill">
                <radgrid:RadGridView.Columns>
                    <radgrid:GridViewDataColumn Header="ID" UniqueName="ID" DataMemberBinding="{Binding ID}" />
                    <radgrid:GridViewDataColumn Header="Name" UniqueName="Name" DataMemberBinding="{Binding Name}" />
                </radgrid:RadGridView.Columns>
            </radgrid:RadGridView>
        </Border>
    </Grid>
</UserControl>

Thanks for your answer.
Regards

[Kalin Milanov]

Hi Marjeta Segrec,

We are aware of this issue and we are looking at a way of fixing it for the future. For now I can only provide you with the following workaround:

Define styles for the both row and alternate row:

<Style x:Key="GridViewRowStyle" TargetType="radgrid:GridViewRow">
    <Setter Property="Background" Value="White" />
</Style>

<Style x:Key="GridViewAlternateRowStyle" TargetType="radgrid:GridViewRow">
    <Setter Property="Background" Value="Gray" />
</Style>

then apply it to the RadGridView as follows:

<radgrid:RadGridView x:Name="RadGrid" AutoGenerateColumns="False" ColumnsWidthMode="Fill" RowStyle="{StaticResource GridViewRowStyle}" AlternateRowStyle="{StaticResource GridViewAlternateRowStyle}">
   <radgrid:RadGridView.Columns>
      <radgrid:GridViewDataColumn Header="ID" UniqueName="ID" DataMemberBinding="{Binding ID}" />
      <radgrid:GridViewDataColumn Header="Name" UniqueName="Name" DataMemberBinding="{Binding Name}" />
   </radgrid:RadGridView.Columns>
</radgrid:RadGridView>

This should force the application of the background of the row when scrolling and will bypass the issue you are having.

Sincerely yours,
Kalin Milanov
the Telerik team

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