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//---------------------------------------------------------------------------
//
// File: JournalConverter.cs
//
// Description: Implements the Converter to limit journal views to 9 items.
//
// Created: 1/31/05 by SujalP
//
// Copyright (C) 2005 by Microsoft Corporation. All rights reserved.
//
//---------------------------------------------------------------------------
// Disable unknown #pragma warning for pragmas we use to exclude certain PreSharp violations
#pragma warning disable 1634, 1691
using System;
using System.Collections;
using System.Collections.Specialized;
using System.Globalization;
using System.ComponentModel;
using System.Windows.Data;
using MS.Internal;
namespace System.Windows.Navigation
{
/// <summary>
/// This class returns an IEnumerable that is limited in length - it is used by the NavigationWindow
/// style to limit how many entries are shown in the back and forward drop down buttons. Not
/// intended to be used in any other situations.
/// </summary>
public sealed class JournalEntryListConverter : IValueConverter
{
/// <summary>
/// This method from IValueConverter returns an IEnumerable which in turn will yield the
/// ViewLimit limited collection of journal back and forward stack entries.
/// </summary>
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
#pragma warning disable 6506
return (value != null) ? ((JournalEntryStack)value).GetLimitedJournalEntryStackEnumerable() : null;
#pragma warning restore 6506
}
/// <summary>
/// This method from IValueConverter returns an IEnumerable which was originally passed to Convert
/// </summary>
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
return Binding.DoNothing;
}
}
/// <summary>
/// Describes the position of the journal entry relative to the current page.
/// </summary>
public enum JournalEntryPosition
{
/// <summary>
/// The entry is on the BackStack
/// </summary>
Back,
/// <summary>
/// The current page
/// </summary>
Current,
/// <summary>
/// The entry on the ForwardStack
/// </summary>
Forward,
}
/// <summary>
/// Puts all of the journal entries into a single list, for an IE7-style menu.
/// </summary>
public sealed class JournalEntryUnifiedViewConverter : IMultiValueConverter
{
/// <summary>
/// The DependencyProperty for the JournalEntryPosition property.
/// </summary>
public static readonly DependencyProperty JournalEntryPositionProperty =
DependencyProperty.RegisterAttached(
"JournalEntryPosition",
typeof(JournalEntryPosition),
typeof(JournalEntryUnifiedViewConverter),
new PropertyMetadata(JournalEntryPosition.Current));
/// <summary>
/// Helper for reading the JournalEntryPosition property.
/// </summary>
public static JournalEntryPosition GetJournalEntryPosition(DependencyObject element)
{
if (element == null)
{
throw new ArgumentNullException("element");
}
return ((JournalEntryPosition)element.GetValue(JournalEntryPositionProperty));
}
/// <summary>
/// Helper for setting the JournalEntryPosition property.
/// </summary>
public static void SetJournalEntryPosition(DependencyObject element, JournalEntryPosition position)
{
if (element == null)
{
throw new ArgumentNullException("element");
}
element.SetValue(JournalEntryPositionProperty, position);
}
/// <summary>
/// This method from IValueConverter returns an IEnumerable which in turn will yield the
/// single list containing all of the menu items.
/// </summary>
public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
if (values != null && values.Length == 2)
{
JournalEntryStack backStack = values[0] as JournalEntryStack;
JournalEntryStack forwardStack = values[1] as JournalEntryStack;
if (backStack != null && forwardStack != null)
{
LimitedJournalEntryStackEnumerable limitedBackStack = (LimitedJournalEntryStackEnumerable)backStack.GetLimitedJournalEntryStackEnumerable();
LimitedJournalEntryStackEnumerable limitedForwardStack = (LimitedJournalEntryStackEnumerable)forwardStack.GetLimitedJournalEntryStackEnumerable();
return new UnifiedJournalEntryStackEnumerable(limitedBackStack, limitedForwardStack);
}
}
return null;
}
/// <summary>
/// This method is unused.
/// </summary>
public object[] ConvertBack(object value, Type[] targetTypes, object parameter, System.Globalization.CultureInfo culture)
{
return new object[] { Binding.DoNothing };
}
}
// Merges LimitedBack and Forward Stack into one list and
internal class UnifiedJournalEntryStackEnumerable : IEnumerable, INotifyCollectionChanged
{
internal UnifiedJournalEntryStackEnumerable(LimitedJournalEntryStackEnumerable backStack, LimitedJournalEntryStackEnumerable forwardStack)
{
_backStack = backStack;
_backStack.CollectionChanged += new NotifyCollectionChangedEventHandler(StacksChanged);
_forwardStack = forwardStack;
_forwardStack.CollectionChanged += new NotifyCollectionChangedEventHandler(StacksChanged);
}
public IEnumerator GetEnumerator()
{
if (_items == null)
{
// Reserve space so this will not have to reallocate. The most it will ever be is
// 9 for the forward stack, 9 for the back stack, 1 for the title bar
_items = new ArrayList(19);
// Add ForwardStack in reverse order
foreach (JournalEntry o in _forwardStack)
{
_items.Insert(0, o);
JournalEntryUnifiedViewConverter.SetJournalEntryPosition(o, JournalEntryPosition.Forward);
}
DependencyObject current = new DependencyObject();
current.SetValue(JournalEntry.NameProperty, SR.Get(SRID.NavWindowMenuCurrentPage));
// "Current Page"
_items.Add(current);
foreach (JournalEntry o in _backStack)
{
_items.Add(o);
JournalEntryUnifiedViewConverter.SetJournalEntryPosition(o, JournalEntryPosition.Back);
}
}
return _items.GetEnumerator();
}
internal void StacksChanged(object sender, NotifyCollectionChangedEventArgs e)
{
_items = null;
if (CollectionChanged != null)
{
CollectionChanged(this, new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
}
}
public event NotifyCollectionChangedEventHandler CollectionChanged;
private LimitedJournalEntryStackEnumerable _backStack, _forwardStack;
private ArrayList _items;
}
}
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