/// <summary>
/// Prepares a new container for a given item.
/// </summary>
/// <remarks>We do not want to call base.PrepareContainerForItemOverride in this override because it will set local values on the header</remarks>
/// <param name="element">The new container.</param>
/// <param name="item">The item that the container represents.</param>
protected override void PrepareContainerForItemOverride(DependencyObject element, object item)
{
DataGridColumnHeader header = element as DataGridColumnHeader;
if (header != null)
{
DataGridColumn column = ColumnFromContainer(header);
Debug.Assert(column != null, "We shouldn't have generated this column header if we don't have a column.");
if (header.Column == null)
{
// A null column means this is a fresh container. PrepareContainer will also be called simply if the column's
// Header property has changed and this container needs to be given a new item. In that case it'll already be tracked.
header.Tracker.Debug_AssertNotInList(_headerTrackingRoot);
header.Tracker.StartTracking(ref _headerTrackingRoot);
}
header.Tracker.Debug_AssertIsInList(_headerTrackingRoot);
header.PrepareColumnHeader(item, column);
}
}
