ComboBox instance set to NULL in XamWebOutlookBar

George posted over 15 years ago

I have a SilverLight Page and within this page I have an XamWebOutlookBar with two OutlookBarGroups in it, inside each of the groups I have different controls including a ComboBox. Before changing my code to use the XamWebOutlookBar the instance of the ComboBox was used inside my page's constructor to set its ItemsSource to a list of strings. as follows.

List<string> list = new List<string>();

list.Add("Item 1");

list.Add("Item 2");

cboxReasons.ItemsSource = list;

And of course the cboxReasons is references other places in the C# code. Now that I've put this ComboBox inside a group in XamWebOutlookBar, its always NULL and I keep hitting a NullReferenceException. I also tried setting the ComboBox's items in the design level (XAML), thinking XamWebOutlookBar instantiates it in a later stages, but the instance is still NULL.

Any help on how to add/set a ComboBox in the XamWebOutlookBar is appreciated.

The following is my XAML.

<navigation:Page

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"

mc:Ignorable="d"

xmlns:navigation="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Navigation"

xmlns:data="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data"

xmlns:controls="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls"

xmlns:controlsToolkit="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Toolkit"

xmlns:igHtmlViewer="clr-namespace:Infragistics.Silverlight.Controls;assembly=Infragistics.Silverlight.XamWebHtmlViewer.v9.2"

xmlns:igOB="clr-namespace:Infragistics.Silverlight.Controls;assembly=Infragistics.Silverlight.XamWebOutlookBar.v9.1"

x:Class="PCRViewerSLite.Views.PcrSearch"

d:DesignWidth="640" d:DesignHeight="480"

Title="PCR Viewer">

<navigation:Page.Resources>

</Button>

</Button>

</StackPanel>

</DataTemplate>

</navigation:Page.Resources>

<Grid.ColumnDefinitions>

</Grid.ColumnDefinitions>

<igOB:XamWebOutlookBar>

<igOB:OutlookBarGroup x:Name="groupSearch" Header="Search" IsSelected="True">

<igOB:OutlookBarGroup.LargeIconTemplate>

</DataTemplate>

</igOB:OutlookBarGroup.LargeIconTemplate>

<Grid.RowDefinitions>

</Grid.RowDefinitions>

<Grid.ColumnDefinitions>

</Grid.ColumnDefinitions>

<CheckBox.Effect>

</CheckBox.Effect>

</CheckBox>

<controls:DatePicker x:Name="datePickerFrom" d:LayoutOverrides="Width, Height" Grid.Row="8" Grid.Column="1"/>

<controls:DatePicker x:Name="datePickerTo" Grid.Column="1" Grid.Row="9" d:LayoutOverrides="Width, Height"/>

</Grid>

</ScrollViewer>

</igOB:OutlookBarGroup>

<igOB:OutlookBarGroup x:Name="groupResults" Header="Results">

<igOB:OutlookBarGroup.LargeIconTemplate>

</DataTemplate>

</igOB:OutlookBarGroup.LargeIconTemplate>

<ScrollViewer x:Name="scrollViewResults" VerticalScrollBarVisibility="Auto"

controlsToolkit:DockPanel.Dock="Left" HorizontalScrollBarVisibility="Auto" FontSize="9.333" HorizontalContentAlignment="Left" VerticalContentAlignment="Top" Height="0" Width="270" d:LayoutOverrides="VerticalAlignment">

</ComboBox>

<data:DataGrid x:Name="dataGridResults" GridLinesVisibility="All" SelectionMode="Single" ScrollViewer.HorizontalScrollBarVisibility="Auto" ScrollViewer.VerticalScrollBarVisibility="Auto" IsReadOnly="True" AutoGenerateColumns="True">

<data:DataGrid.Columns>

<data:DataGridTemplateColumn CellTemplate="{StaticResource ViewButtons}"/>

</data:DataGrid.Columns>

</data:DataGrid>

</StackPanel>

</ScrollViewer>

</igOB:OutlookBarGroup>

</igOB:XamWebOutlookBar>

<igHtmlViewer:XamWebHtmlViewer x:Name="htmlViewer" ScrollViewer.HorizontalScrollBarVisibility="Auto" ScrollViewer.VerticalScrollBarVisibility="Auto" Grid.Column="1" d:LayoutOverrides="Width, Height" Background="{StaticResource Theme_Color1}"/>

</Grid>

</navigation:Page>

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Ninos posted over 15 years ago

The same thing happens when the DataGrid instance is referenced in the code to populate its ItemsSource.

It seems like XamWebOutlookBar is not instantiating its controls, or is there a magical way to do that that's not documented?

Thanks,

Ninos
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[Infragistics] Stoimen Gerenski posted over 15 years ago in reply to Ninos

Hi gsarkis / Ninos

This behavior is by design. As a workaround, you could use an approach which is demonstrated by the following sample:

<UserControl x:Class="TestApp.Groups"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:w="clr-namespace:System.Windows;assembly=System.Windows"
             xmlns:igOB="clr-namespace:Infragistics.Silverlight.Controls;assembly=Infragistics.Silverlight.XamWebOutlookBar.v9.1"
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
             mc:Ignorable="d">
    <Grid x:Name="LayoutRoot">
        <igOB:XamWebOutlookBar x:Name="MyOutlookBar">
            <igOB:OutlookBarGroup Key="ComboGroup">
                <ComboBox>
                    <ComboBoxItem Content="ComboItem1"/>
                    <ComboBoxItem Content="ComboItem2"/>
                </ComboBox>
            </igOB:OutlookBarGroup>
        </igOB:XamWebOutlookBar>
    </Grid>
</UserControl>

   public partial class Groups : UserControl
    {
        public Groups()
        {
            InitializeComponent();

            ComboBox myCombo = null;

            myCombo = this.MyOutlookBar.Groups["ComboGroup"].Content as ComboBox;
        }
    }

I hope this will solve your issue and no inconvenience will be caused.

Regards,
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