protected override Size MeasureOverride(Size availableSize)
{
Panel panel = this.GroupLevelIndicatorPaneHost;
if (panel == null)
{
return(base.MeasureOverride(availableSize));
}
DataGridContext dataGridContext = DataGridControl.GetDataGridContext(this);
if (dataGridContext != null)
{
ObservableCollection <GroupDescription> groupDescriptions = DataGridContext.GetGroupDescriptionsHelper(dataGridContext.Items);
int leafGroupLevel = GroupLevelIndicatorPane.GetGroupLevel(this);
// If Indented is true (default), we use the total groupDescriptions.Count for this DataGridContext
int correctedGroupLevel = (this.Indented == true) ? groupDescriptions.Count : leafGroupLevel;
// Ensure that the GroupLevel retrieved does not exceeds the number of group descriptions for the DataGridContext
correctedGroupLevel = Math.Min(correctedGroupLevel, groupDescriptions.Count);
// Then finally, if the GroupLevel is -1, then indent at maximum.
if (correctedGroupLevel == -1)
{
correctedGroupLevel = groupDescriptions.Count;
}
if ((correctedGroupLevel > 0) &&
(this.AreGroupsFlattened))
{
correctedGroupLevel = (this.Indented) ? 1 : 0;
}
UIElementCollection children = panel.Children;
int childrenCount = children.Count;
// If we need to add/remove GroupLevelIndicators from the panel
if (correctedGroupLevel != childrenCount)
{
// When grouping change, we take for granted that the group deepness will change,
// so we initialize DataContext of the margin only in there.
// Clear all the panel's children!
children.Clear();
// Create 1 group margin content presenter for each group level
for (int i = correctedGroupLevel - 1; i >= 0; i--)
{
GroupLevelIndicator groupMargin = new GroupLevelIndicator();
groupMargin.DataContext = dataGridContext.GroupLevelDescriptions[i];
children.Insert(0, new GroupLevelIndicator());
}
childrenCount = correctedGroupLevel;
this.SetCurrentIndicatorCount(childrenCount);
}
object item = dataGridContext.GetItemFromContainer(this);
for (int i = 0; i < childrenCount; i++)
{
GroupLevelIndicator groupMargin = children[i] as GroupLevelIndicator;
CollectionViewGroup groupForIndicator = GroupLevelIndicatorPane.GetCollectionViewGroupHelper(
dataGridContext, groupDescriptions, item, i);
GroupConfiguration groupLevelConfig = GroupConfiguration.GetGroupConfiguration(
dataGridContext, groupDescriptions, dataGridContext.GroupConfigurationSelector, i, groupForIndicator);
if (groupLevelConfig != null)
{
Binding groupLevelIndicatorStyleBinding = BindingOperations.GetBinding(groupMargin, GroupLevelIndicator.StyleProperty);
if ((groupLevelIndicatorStyleBinding == null) || (groupLevelIndicatorStyleBinding.Source != groupLevelConfig))
{
groupLevelIndicatorStyleBinding = new Binding("GroupLevelIndicatorStyle");
groupLevelIndicatorStyleBinding.Source = groupLevelConfig;
groupMargin.SetBinding(GroupLevelIndicator.StyleProperty, groupLevelIndicatorStyleBinding);
}
}
else
{
groupMargin.ClearValue(GroupLevelIndicator.StyleProperty);
}
// If the ShowIndicators property is False or there is already leafGroupLevel GroupLevelIndicators in the panel,
// the current newGroupMargin must be hidden.
if ((!GroupLevelIndicatorPane.GetShowIndicators(this)) || ((i >= leafGroupLevel) && (leafGroupLevel != -1)))
{
groupMargin.Visibility = Visibility.Hidden;
}
else
{
groupMargin.Visibility = Visibility.Visible;
}
}
}
return(base.MeasureOverride(availableSize));
}
