/// <summary>
/// Updates the selected <see cref="DataGridColumnHeader"/>.
/// </summary>
/// <param name="datagrid">The datagrid.</param>
private static void UpdateSelectedHeaders(DataGridControl datagrid)
{
if (null == datagrid)
{
return;
}
// Get the list of headers
IList <DependencyObject> headers = VisualTreeHelperExtended.GetAllDescendants(datagrid, typeof(DataGridColumnHeader));
if (null == headers || 0 == headers.Count)
{
return;
}
// Update the selection based on the current tracking modes
SelectionTrackingModes trackingModes = GetTrackingModes(datagrid);
if (0 != (trackingModes & SelectionTrackingModes.Headers))
{
// Update header selections, if any
foreach (DataGridColumnHeader header in headers)
{
// Determine if the column associated with this header has any selected cells
bool isSelected = false;
foreach (DataGridCellInfo cellInfo in datagrid.SelectedCells)
{
if (cellInfo.Column == header.Column)
{
isSelected = true;
break;
}
}
// Update the selection for this header
if (isSelected != GetIsSelectedHeader(header))
{
if (isSelected)
{
header.SetValue(IsSelectedHeaderPropertyKey, true);
}
else
{
header.ClearValue(IsSelectedHeaderPropertyKey);
}
}
}
}
else
{
// Clear header selections, if any
foreach (DataGridColumnHeader header in headers)
{
if (GetIsSelectedHeader(header))
{
header.ClearValue(IsSelectedHeaderPropertyKey);
}
}
}
}
public static void SetTrackingModes(DataGridControl obj, SelectionTrackingModes value)
{
if (null == obj)
{
throw new ArgumentNullException("obj");
}
obj.SetValue(SelectionBehavior.TrackingModesProperty, value);
}
/// <summary>
/// Called when <see cref="TrackingModesProperty"/> is changed.
/// </summary>
/// <param name="d">The dependency object that was changed.</param>
/// <param name="e">The <see cref="DependencyPropertyChangedEventArgs"/> instance containing the event data.</param>
private static void OnTrackingModesPropertyValueChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
DataGridControl datagrid = d as DataGridControl;
if (null == datagrid)
{
return;
}
SelectionTrackingModes trackingModes = (SelectionTrackingModes)e.NewValue;
if (SelectionTrackingModes.None != trackingModes)
{
datagrid.SelectedCellsChanged += new SelectedCellsChangedEventHandler(OnDatagridSelectedCellsChanged);
}
else
{
datagrid.SelectedCellsChanged -= new SelectedCellsChangedEventHandler(OnDatagridSelectedCellsChanged);
}
UpdateSelectedHeaders(datagrid);
}