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//---------------------------------------------------------------------------
//
// <copyright file="GroupStyle.cs" company="Microsoft">
// Copyright (C) 2003 by Microsoft Corporation. All rights reserved.
// </copyright>
//
//
// Description: Description of UI for grouping.
//
// See spec at http://avalon/connecteddata/Specs/Grouping.mht
//
//---------------------------------------------------------------------------
using System.ComponentModel; // [DefaultValue]
using System.Windows.Data; // CollectionViewGroup
namespace System.Windows.Controls
{
/// <summary>
/// The GroupStyle describes how to display the items in a GroupCollection,
/// such as the collection obtained from CollectionViewGroup.Items.
/// </summary>
[Localizability(LocalizationCategory.None, Readability = Readability.Unreadable)] // cannot be read & localized as string
public class GroupStyle : INotifyPropertyChanged
{
#region Constructors
//------------------------------------------------------
//
// Constructors
//
//------------------------------------------------------
/// <summary>
/// Initializes a new instance of GroupStyle.
/// </summary>
public GroupStyle()
{
}
static GroupStyle()
{
ItemsPanelTemplate template = new ItemsPanelTemplate(new FrameworkElementFactory(typeof(StackPanel)));
template.Seal();
DefaultGroupPanel = template;
DefaultStackPanel = template;
template = new ItemsPanelTemplate(new FrameworkElementFactory(typeof(VirtualizingStackPanel)));
template.Seal();
DefaultVirtualizingStackPanel = template;
s_DefaultGroupStyle = new GroupStyle();
}
#endregion Constructors
#region INotifyPropertyChanged
/// <summary>
/// This event is raised when a property of the group style has changed.
/// </summary>
event PropertyChangedEventHandler INotifyPropertyChanged.PropertyChanged
{
add
{
PropertyChanged += value;
}
remove
{
PropertyChanged -= value;
}
}
/// <summary>
/// PropertyChanged event (per <see cref="INotifyPropertyChanged" />).
/// </summary>
protected virtual event PropertyChangedEventHandler PropertyChanged;
/// <summary>
/// A subclass can call this method to raise the PropertyChanged event.
/// </summary>
protected virtual void OnPropertyChanged(PropertyChangedEventArgs e)
{
if (PropertyChanged != null)
{
PropertyChanged(this, e);
}
}
#endregion INotifyPropertyChanged
#region Public Properties
//------------------------------------------------------
//
// Public Properties
//
//------------------------------------------------------
/// <summary>
/// A template that creates the panel used to layout the items.
/// </summary>
public ItemsPanelTemplate Panel
{
get { return _panel; }
set
{
_panel = value;
OnPropertyChanged("Panel");
}
}
/// <summary>
/// ContainerStyle is the style that is applied to the GroupItem generated
/// for each item.
/// </summary>
[DefaultValue(null)]
public Style ContainerStyle
{
get { return _containerStyle; }
set { _containerStyle = value; OnPropertyChanged("ContainerStyle"); }
}
/// <summary>
/// ContainerStyleSelector allows the app writer to provide custom style selection logic
/// for a style to apply to each generated GroupItem.
/// </summary>
[DefaultValue(null)]
public StyleSelector ContainerStyleSelector
{
get { return _containerStyleSelector; }
set { _containerStyleSelector = value; OnPropertyChanged("ContainerStyleSelector"); }
}
/// <summary>
/// HeaderTemplate is the template used to display the group header.
/// </summary>
[DefaultValue(null)]
public DataTemplate HeaderTemplate
{
get { return _headerTemplate; }
set { _headerTemplate = value; OnPropertyChanged("HeaderTemplate"); }
}
/// <summary>
/// HeaderTemplateSelector allows the app writer to provide custom selection logic
/// for a template used to display the group header.
/// </summary>
[DefaultValue(null)]
public DataTemplateSelector HeaderTemplateSelector
{
get { return _headerTemplateSelector; }
set { _headerTemplateSelector = value; OnPropertyChanged("HeaderTemplateSelector"); }
}
/// <summary>
/// HeaderStringFormat is the format used to display the header content as a string.
/// This arises only when no template is available.
/// </summary>
[DefaultValue(null)]
public String HeaderStringFormat
{
get { return _headerStringFormat; }
set { _headerStringFormat = value; OnPropertyChanged("HeaderStringFormat"); }
}
/// <summary>
/// HidesIfEmpty allows the app writer to indicate whether items corresponding
/// to empty groups should be displayed.
/// </summary>
[DefaultValue(false)]
public bool HidesIfEmpty
{
get { return _hidesIfEmpty; }
set { _hidesIfEmpty = value; OnPropertyChanged("HidesIfEmpty"); }
}
/// <summary>
/// AlternationCount controls the range of values assigned to the
/// ItemsControl.AlternationIndex property on containers generated
/// for this level of grouping.
[DefaultValue(0)]
public int AlternationCount
{
get { return _alternationCount; }
set
{
_alternationCount = value;
_isAlternationCountSet = true;
OnPropertyChanged("AlternationCount");
}
}
/// <summary>The default panel template.</summary>
public static readonly ItemsPanelTemplate DefaultGroupPanel;
/// <summary>The default GroupStyle.</summary>
public static GroupStyle Default
{
get { return s_DefaultGroupStyle; }
}
#endregion Public Properties
#region Private Properties
private void OnPropertyChanged(string propertyName)
{
OnPropertyChanged(new PropertyChangedEventArgs(propertyName));
}
internal bool IsAlternationCountSet
{
get { return _isAlternationCountSet; }
}
#endregion Private Properties
#region Private Fields
//------------------------------------------------------
//
// Private Fields
//
//------------------------------------------------------
ItemsPanelTemplate _panel;
Style _containerStyle;
StyleSelector _containerStyleSelector;
DataTemplate _headerTemplate;
DataTemplateSelector _headerTemplateSelector;
string _headerStringFormat;
bool _hidesIfEmpty;
bool _isAlternationCountSet;
int _alternationCount;
static GroupStyle s_DefaultGroupStyle;
/// <summary>The default panel template.</summary>
internal static ItemsPanelTemplate DefaultStackPanel;
internal static ItemsPanelTemplate DefaultVirtualizingStackPanel;
#endregion Private Fields
}
/// <summary>
/// A delegate to select the group style as a function of the
/// parent group and its level.
/// </summary>
public delegate GroupStyle GroupStyleSelector(CollectionViewGroup group, int level);
}
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