/// <summary>
/// Handles a change to the column property.
/// </summary>
/// <param name="sender">The Object that originated the event.</param>
/// <param name="propertyChangedEventArgs">The event arguments.</param>
protected override void OnColumnPropertyChanged(Object sender, PropertyChangedEventArgs propertyChangedEventArgs)
{
// Validate the parameters.
if (sender == null)
{
throw new ArgumentNullException("sender");
}
if (propertyChangedEventArgs == null)
{
throw new ArgumentNullException("propertyChangedEventArgs");
}
// This will get the column where the property change occurred from the sender.
ColumnViewColumn columnViewColumn = sender as ColumnViewColumn;
// If the column is visible, then it has a visual element which needs to have its properties reconciled with the ColumnViewColumn properties.
if (columnViewColumn.IsVisible)
{
// This will find the visual element what has properites that must be reconciled with the header.
Int32 columnIndex = this.Columns.IndexOf(columnViewColumn);
ColumnViewColumnCell columnViewColumnCell = this.Children[columnIndex] as ColumnViewColumnCell;
// This will apply the property in the column to the visual element representing that column in the current row.
switch (propertyChangedEventArgs.PropertyName)
{
case "CellTemplate":
case "CellTemplateSelector":
case "DisplayMemberBinding":
// Recreate the cell based on the new properties.
this.Children.RemoveAt(columnIndex);
FrameworkElement frameworkElement = ColumnViewRowPresenter.CreateCell(columnViewColumn);
this.InstallCell(frameworkElement, columnViewColumn);
this.Children.Insert(columnIndex, frameworkElement);
break;
case "Width":
case "MinWidth":
// Forcing a re-measurement of the row will pick up the changes made to the column's width.
this.InvalidateMeasure();
break;
}
}
}
/// <summary>
/// Handles a change to the column collection.
/// </summary>
/// <param name="notifyCollectionChangedEventArgs">The Object that originated the event.</param>
/// <param name="notifyCollectionChangedEventArgs">Provides data for the CollectionChanged event.</param>
protected override void OnColumnCollectionChanged(Object sender, NotifyCollectionChangedEventArgs notifyCollectionChangedEventArgs)
{
Int32 columnIndex;
// Validate the parameters.
if (sender == null)
{
throw new ArgumentNullException("sender");
}
if (notifyCollectionChangedEventArgs == null)
{
throw new ArgumentNullException("notifyCollectionChangedEventArgs");
}
// This will reconcile the visual elements in this control with the definition of the columns.
switch (notifyCollectionChangedEventArgs.Action)
{
case NotifyCollectionChangedAction.Add:
// Create a cell to hold the value and add each it to the row at the given index.
columnIndex = notifyCollectionChangedEventArgs.NewStartingIndex == -1 ? 0 : notifyCollectionChangedEventArgs.NewStartingIndex;
foreach (ColumnViewColumn columnViewColumn in notifyCollectionChangedEventArgs.NewItems)
{
if (columnViewColumn.IsVisible)
{
FrameworkElement frameworkElement = ColumnViewRowPresenter.CreateCell(columnViewColumn);
this.InstallCell(frameworkElement, columnViewColumn);
this.Children.Insert(columnIndex++, frameworkElement);
}
this.InvalidateMeasure();
}
break;
case NotifyCollectionChangedAction.Move:
// Columns that appear after the visible count in the collection are hidden items. They exist only as a pool of potential columns. The items below
// the 'VisibleCount' are actually visible in this view and appear in the same order in which they appear in this control. As items are moved in
// and out of the visible range, we will create or destroy the visual elements used to show those columns in the viewer.
Int32 oldIndex = notifyCollectionChangedEventArgs.OldStartingIndex;
Int32 newIndex = notifyCollectionChangedEventArgs.NewStartingIndex;
ColumnViewColumn movedColumn = this.Columns[newIndex];
if (this.Children.Count == this.Columns.VisibleCount)
{
// At this point, the collection hasn't changed. We are just moving columns around.
UIElement uiElement = this.Children[oldIndex];
this.Children.RemoveAt(notifyCollectionChangedEventArgs.OldStartingIndex);
this.Children.Insert(notifyCollectionChangedEventArgs.NewStartingIndex, uiElement);
this.InvalidateArrange();
}
else
{
// This will hide the column by destroying the visual elements used to display the column.
if (oldIndex < this.Children.Count)
{
this.Children.RemoveAt(oldIndex);
}
// This will create a visual element to display the now visible column.
if (movedColumn.IsVisible)
{
FrameworkElement frameworkElement = ColumnViewRowPresenter.CreateCell(movedColumn);
this.InstallCell(frameworkElement, movedColumn);
this.Children.Insert(newIndex, frameworkElement);
}
}
break;
case NotifyCollectionChangedAction.Remove:
// Remove the offending cells from the specified location.
columnIndex = notifyCollectionChangedEventArgs.OldStartingIndex;
foreach (ColumnViewColumn columnViewColumn in notifyCollectionChangedEventArgs.OldItems)
{
this.RemoveCell(columnIndex++);
}
break;
case NotifyCollectionChangedAction.Reset:
// Clear them all.
while (this.Children.Count != 0)
{
this.RemoveCell(0);
}
break;
}
}
