Comment préserver le contrôle de l'etat dans l'onglet éléments dans un TabControl

L'Écrivain exemple d'application de la Application WPF Cadre (WAF) montre comment résoudre votre problème. Il crée un nouveau contrôle utilisateur pour chaque TabItem. Si l'état est conservé lorsque l'utilisateur change de l'Onglet actif.

j'ai eu le même problème et trouvé une solution sympa vous pouvez l'utiliser comme un normal TabControl autant que je l'ai testé. Dans le cas où il important pour vous ici le Licence Actuelle

Ici le Code de la cas, le Lien va vers le bas:

using System;
using System.Collections.Specialized;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
namespace CefSharp.Wpf.Example.Controls
{
///<summary>
///Extended TabControl which saves the displayed item so you don't get the performance hit of
///unloading and reloading the VisualTree when switching tabs
///</summary>
///<remarks>
///Based on example from http://stackoverflow.com/a/9802346, which in turn is based on
///http://www.pluralsight-training.net/community/blogs/eburke/archive/2009/04/30/keeping-the-wpf-tab-control-from-destroying-its-children.aspx
///with some modifications so it reuses a TabItem's ContentPresenter when doing drag/drop operations
///</remarks>
[TemplatePart(Name = "PART_ItemsHolder", Type = typeof(Panel))]
public class NonReloadingTabControl : TabControl
{
private Panel itemsHolderPanel;
public NonReloadingTabControl()
{
//This is necessary so that we get the initial databound selected item
ItemContainerGenerator.StatusChanged += ItemContainerGeneratorStatusChanged;
}
///<summary>
///If containers are done, generate the selected item
///</summary>
///<param name="sender">The sender.</param>
///<param name="e">The <see cref="EventArgs"/> instance containing the event data.</param>
private void ItemContainerGeneratorStatusChanged(object sender, EventArgs e)
{
if (ItemContainerGenerator.Status == GeneratorStatus.ContainersGenerated)
{
ItemContainerGenerator.StatusChanged -= ItemContainerGeneratorStatusChanged;
UpdateSelectedItem();
}
}
///<summary>
///Get the ItemsHolder and generate any children
///</summary>
public override void OnApplyTemplate()
{
base.OnApplyTemplate();
itemsHolderPanel = GetTemplateChild("PART_ItemsHolder") as Panel;
UpdateSelectedItem();
}
///<summary>
///When the items change we remove any generated panel children and add any new ones as necessary
///</summary>
///<param name="e">The <see cref="NotifyCollectionChangedEventArgs"/> instance containing the event data.</param>
protected override void OnItemsChanged(NotifyCollectionChangedEventArgs e)
{
base.OnItemsChanged(e);
if (itemsHolderPanel == null)
return;
switch (e.Action)
{
case NotifyCollectionChangedAction.Reset:
itemsHolderPanel.Children.Clear();
break;
case NotifyCollectionChangedAction.Add:
case NotifyCollectionChangedAction.Remove:
if (e.OldItems != null)
{
foreach (var item in e.OldItems)
{
var cp = FindChildContentPresenter(item);
if (cp != null)
itemsHolderPanel.Children.Remove(cp);
}
}
//Don't do anything with new items because we don't want to
//create visuals that aren't being shown
UpdateSelectedItem();
break;
case NotifyCollectionChangedAction.Replace:
throw new NotImplementedException("Replace not implemented yet");
}
}
protected override void OnSelectionChanged(SelectionChangedEventArgs e)
{
base.OnSelectionChanged(e);
UpdateSelectedItem();
}
private void UpdateSelectedItem()
{
if (itemsHolderPanel == null)
return;
//Generate a ContentPresenter if necessary
var item = GetSelectedTabItem();
if (item != null)
CreateChildContentPresenter(item);
//show the right child
foreach (ContentPresenter child in itemsHolderPanel.Children)
child.Visibility = ((child.Tag as TabItem).IsSelected) ? Visibility.Visible : Visibility.Collapsed;
}
private ContentPresenter CreateChildContentPresenter(object item)
{
if (item == null)
return null;
var cp = FindChildContentPresenter(item);
if (cp != null)
return cp;
var tabItem = item as TabItem;
cp = new ContentPresenter
{
Content = (tabItem != null) ? tabItem.Content : item,
ContentTemplate = this.SelectedContentTemplate,
ContentTemplateSelector = this.SelectedContentTemplateSelector,
ContentStringFormat = this.SelectedContentStringFormat,
Visibility = Visibility.Collapsed,
Tag = tabItem ?? (this.ItemContainerGenerator.ContainerFromItem(item))
};
itemsHolderPanel.Children.Add(cp);
return cp;
}
private ContentPresenter FindChildContentPresenter(object data)
{
if (data is TabItem)
data = (data as TabItem).Content;
if (data == null)
return null;
if (itemsHolderPanel == null)
return null;
foreach (ContentPresenter cp in itemsHolderPanel.Children)
{
if (cp.Content == data)
return cp;
}
return null;
}
protected TabItem GetSelectedTabItem()
{
var selectedItem = SelectedItem;
if (selectedItem == null)
return null;
var item = selectedItem as TabItem ?? ItemContainerGenerator.ContainerFromIndex(SelectedIndex) as TabItem;
return item;
}
}
}

Licence à Copietime

//Copyright © 2010-2016 The CefSharp Authors
//
//Redistribution and use in source and binary forms, with or without
//modification, are permitted provided that the following conditions are
//met:
//
//   * Redistributions of source code must retain the above copyright
//     notice, this list of conditions and the following disclaimer.
//
//   * Redistributions in binary form must reproduce the above
//     copyright notice, this list of conditions and the following disclaimer
//     in the documentation and/or other materials provided with the
//     distribution.
//
//   * Neither the name of Google Inc. nor the name Chromium Embedded
//     Framework nor the name CefSharp nor the names of its contributors
//     may be used to endorse or promote products derived from this software
//     without specific prior written permission.
//
//THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
//"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
//LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
//A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
//OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
//SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
//LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
//DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
//THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
//(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
//OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Basé sur @Arsen la réponse ci-dessus, c'est un autre problème, que:

1. N'a pas besoin de références supplémentaires. (sauf si vous mettez le code dans une bibliothèque externe)
2. Il n'utilisez pas de classe de base.
3. Il gère à la fois le Reset et Ajouter la collection des changements.

Utiliser

Déclarer l'espace de noms dans le code xaml:

<ResourceDictionary
...
xmlns:behaviors="clr-namespace:My.Behaviors;assembly=My.Wpf.Assembly"
...
>

Mettre à jour le style:

<Style TargetType="TabControl" x:Key="TabControl">
...
<Setter Property="behaviors:TabControlBehavior.DoNotCacheControls" Value="True" />
...
</Style>

Ou mise à jour le TabControl directement:

<TabControl behaviors:TabControlBehavior.DoNotCacheControls="True" ItemsSource="{Binding Tabs}" SelectedItem="{Binding SelectedTab}">

Et voici le code pour le comportement:

using System.Collections;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Windows;
using System.Windows.Controls;
namespace My.Behaviors
{
///<summary>
///Wraps tab item contents in UserControl to prevent TabControl from re-using its content
///</summary>
public class TabControlBehavior
{
private static readonly HashSet<TabControl> _tabControls = new HashSet<TabControl>();
private static readonly Dictionary<ItemCollection, TabControl> _tabControlItemCollections = new Dictionary<ItemCollection, TabControl>();
public static bool GetDoNotCacheControls(TabControl tabControl)
{
return (bool)tabControl.GetValue(DoNotCacheControlsProperty);
}
public static void SetDoNotCacheControls(TabControl tabControl, bool value)
{
tabControl.SetValue(DoNotCacheControlsProperty, value);
}
public static readonly DependencyProperty DoNotCacheControlsProperty = DependencyProperty.RegisterAttached(
"DoNotCacheControls",
typeof(bool),
typeof(TabControlBehavior),
new UIPropertyMetadata(false, OnDoNotCacheControlsChanged));
private static void OnDoNotCacheControlsChanged(
DependencyObject depObj,
DependencyPropertyChangedEventArgs e)
{
var tabControl = depObj as TabControl;
if (null == tabControl)
return;
if (e.NewValue is bool == false)
return;
if ((bool)e.NewValue)
Attach(tabControl);
else
Detach(tabControl);
}
private static void Attach(TabControl tabControl)
{
if (!_tabControls.Add(tabControl))
return;
_tabControlItemCollections.Add(tabControl.Items, tabControl);
((INotifyCollectionChanged)tabControl.Items).CollectionChanged += TabControlUcWrapperBehavior_CollectionChanged;
}
private static void Detach(TabControl tabControl)
{
if (!_tabControls.Remove(tabControl))
return;
_tabControlItemCollections.Remove(tabControl.Items);
((INotifyCollectionChanged)tabControl.Items).CollectionChanged -= TabControlUcWrapperBehavior_CollectionChanged;
}
private static void TabControlUcWrapperBehavior_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
var itemCollection = (ItemCollection)sender;
var tabControl = _tabControlItemCollections[itemCollection];
IList items;
if (e.Action == NotifyCollectionChangedAction.Reset)
{   /* our ObservableArray<T> swops out the whole collection */
items = (ItemCollection)sender;
}
else
{
if (e.Action != NotifyCollectionChangedAction.Add)
return;
items = e.NewItems;
}
foreach (var newItem in items)
{
var ti = tabControl.ItemContainerGenerator.ContainerFromItem(newItem) as TabItem;
if (ti != null)
{
var userControl = ti.Content as UserControl;
if (null == userControl)
ti.Content = new UserControl { Content = ti.Content };
}
}
}
}
}