protected override void InsertItem(int index, object item)
{
if (item is DataTemplate)
{
base.InsertItem(index, item);
}
else
{
GroupHeaderFooterItemTemplate vwc = item as GroupHeaderFooterItemTemplate;
if (vwc != null)
{
if (vwc.Template == null)
{
throw new ArgumentException("A VisibleWhenCollapsed object must have its Template property set to an instance of a DataTemplate.");
}
else
{
base.InsertItem(index, item);
}
}
else
{
throw new ArgumentException("Group headers and footers can only receive ClearHeadersFooters, DataTemplate, or VisibleWhenCollapsed objects.");
}
}
}
static GroupConfiguration()
{
GroupConfiguration.HeadersProperty = GroupConfiguration.HeadersPropertyKey.DependencyProperty;
GroupConfiguration.FootersProperty = GroupConfiguration.FootersPropertyKey.DependencyProperty;
DefaultHeaderTemplate = new GroupHeaderFooterItemTemplate();
DefaultHeaderTemplate.VisibleWhenCollapsed = true;
DefaultHeaderTemplate.Template = new DataTemplate();
DefaultHeaderTemplate.Template.VisualTree = new FrameworkElementFactory(typeof(GroupHeaderControl));
DefaultHeaderTemplate.Template.Seal();
DefaultHeaderTemplate.Seal();
DefaultGroupConfiguration = new GroupConfiguration();
DefaultGroupConfiguration.AddDefaultHeadersFooters();
DefaultGroupConfiguration.Freeze();
}
