Nico Oprescu said:

But I would like to change the header of the RecordSelector to contain also a checkbox, with the select all functionality.

Hi Nico,

I don't understand what this means.  Please clarify what it means to have "select all functionality" exposed in the header of a RecordSelector.  What is the "all" that is being selected?  All of the child records?  All of the checkboxes in the record? What is the problem that you're facing when trying to implement this?

Thanks,

Josh

I moled the XamDataGrid's visual tree and discovered that the field labels are all contained within a Grid panel.  The "header" of the row selectors "column" is really just some empty space in that Grid.  So, with a little XAML magic, and the use of the endlessly useful Infragistics.Windows.Utilities class, I found a way to put a CheckBox in that empty area.  Here's what I did...

<igDP:XamDataGrid DataSource="{Binding}">
  <igDP:XamDataGrid.Resources>
    <Style TargetType="{x:Type igDP:RecordSelector}">
      <Setter Property="Template">
        <Setter.Value>
          <ControlTemplate TargetType="{x:Type  igDP:RecordSelector}">
            <CheckBox
              IsChecked="{Binding Path=DataItem.Selected, Mode=TwoWay}"
              VerticalAlignment="Center"
              HorizontalAlignment="Center"
              />
          </ControlTemplate>
        </Setter.Value>
      </Setter>
    </Style>
  </igDP:XamDataGrid.Resources>
  <igDP:XamDataGrid.FieldLayouts>
    <igDP:FieldLayout>
      <igDP:FieldLayout.Fields>
        <igDP:Field Name="Name">
          <igDP:Field.Settings>
            <igDP:FieldSettings>
              <igDP:FieldSettings.LabelPresenterStyle>
                <Style TargetType="{x:Type igDP:LabelPresenter}">
                  <EventSetter Event="Loaded" Handler="OnNameLabelLoaded" />
                </Style>
              </igDP:FieldSettings.LabelPresenterStyle>
            </igDP:FieldSettings>
          </igDP:Field.Settings>
        </igDP:Field>
        <igDP:Field Name="Status" />
      </igDP:FieldLayout.Fields>
    </igDP:FieldLayout>
  </igDP:XamDataGrid.FieldLayouts>
</igDP:XamDataGrid>

void OnNameLabelLoaded(object sender, RoutedEventArgs e)
{
    // using Infragistics.Windows
    FrameworkElement site = Utilities.GetAncestorFromName(
        e.OriginalSource as DependencyObject,
        "PART_HeaderContentSite");

    if (site == null)
        return;

    Grid siteHost = Utilities.GetAncestorFromType(
        site,
        typeof(Grid),
        false)
        as Grid;

    if (siteHost == null)
        return;

    foreach (UIElement elem in siteHost.Children)
        if (elem is CheckBox)
            return;

    CheckBox chk = new CheckBox();
    chk.Click += new RoutedEventHandler(chk_Click);
    Grid.SetColumnSpan(chk, 3);           
    chk.Margin = new Thickness(4, 0, 0, 0);
    chk.VerticalAlignment = VerticalAlignment.Center;

    siteHost.Children.Add(chk);
}

void chk_Click(object sender, RoutedEventArgs e)
{
    // TODO: Check/uncheck all other CheckBoxes.
}

The best way to understand the structure of any WPF control's element tree is to use the free Mole and Snoop tools.  I use those tools all the time when trying to do customizations of a control.