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Viewing changes to src/AddIns/Misc/PackageManagement/Project/Src/SelectedListBoxItemScrollingBehaviour.cs

  • Committer: sk
  • Date: 2011-09-10 05:17:57 UTC
  • Revision ID: halega@halega.com-20110910051757-qfouz1llya9m6boy
4.1.0.7915 Release Candidate 1

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src/AddIns/Misc/PackageManagement/Project/Src/SelectedListBoxItemScrollingBehaviour.cs
 
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// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
 
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// This code is distributed under the GNU LGPL (for details please see \doc\license.txt)
 
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using System;
 
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using System.Collections;
 
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using System.Windows;
 
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using System.Windows.Controls;
 
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namespace ICSharpCode.PackageManagement
 
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{
 
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        public class SelectedListBoxItemScrollingBehaviour
 
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        {
 
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                ListBox listBox;
 
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                DependencyPropertyChangedEventArgs propertyChangedEventArgs;
 
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                public SelectedListBoxItemScrollingBehaviour(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e)
 
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                {
 
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                        this.listBox = dependencyObject as ListBox;
 
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                        this.propertyChangedEventArgs = e;
 
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                }
 
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                public void Update()
 
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                {
 
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                        if (ShouldUpdateSelectionChangedHandlerRegistration()) {
 
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                                UpdateSelectionChangedHandlerRegistration();
 
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                        }
 
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                }
 
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                bool ShouldUpdateSelectionChangedHandlerRegistration()
 
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                {
 
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                        return DependencyObjectIsListBox() && NewPropertyValueIsBoolean();
 
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                }
 
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                bool DependencyObjectIsListBox()
 
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                {
 
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                        return (listBox != null);
 
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                }
 
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                bool NewPropertyValueIsBoolean()
 
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                {
 
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                        return (propertyChangedEventArgs.NewValue is bool);
 
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                }
 
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                void UpdateSelectionChangedHandlerRegistration()
 
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                {
 
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                        if ((bool)propertyChangedEventArgs.NewValue) {
 
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                                RegisterSelectionChangedHandler(listBox);
 
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                        } else {
 
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                                UnregisterSelectionChangedHandler(listBox);
 
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                        }
 
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                }
 
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                protected virtual void RegisterSelectionChangedHandler(ListBox listBox)
 
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                {
 
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                        listBox.SelectionChanged += OnListBoxSelectionChanged;
 
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                }
 
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                protected virtual void UnregisterSelectionChangedHandler(ListBox listBox)
 
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                {
 
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                        listBox.SelectionChanged -= OnListBoxSelectionChanged;
 
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                }
 
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                static void OnListBoxSelectionChanged(object sender, SelectionChangedEventArgs e)
 
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                {
 
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                        OnListBoxSelectionChanged(sender, e.OriginalSource, e.AddedItems, ScrollListBoxItemIntoView);
 
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                }
 
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                static void ScrollListBoxItemIntoView(ListBox listBox, object item)
 
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                {
 
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                        listBox.ScrollIntoView(item);
 
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                }
 
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                protected static void OnListBoxSelectionChanged(object sender,
 
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                        object originalSource,
 
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                        IList addedItems,
 
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                        Action<ListBox, object> executeScrollListBoxItemIntoView)
 
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                {
 
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                        if (!Object.ReferenceEquals(sender, originalSource)) {
 
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                                return;
 
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                        }
 
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                        ListBox listBox = originalSource as ListBox;
 
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                        if (listBox != null) {
 
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                                if (addedItems.Count > 0) {
 
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                                        executeScrollListBoxItemIntoView(listBox, addedItems[0]);
 
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                                }
 
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                        }
 
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                }
 
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        }
 
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}