How to sort TabItems in the TabControl

Question

I have a collection of type Page with an Order property, I set ItemsSource property of a TabControl an ObservableCollection. What I need to whenever I changed the Order property of an Entity the related TabItem go in the correct location.

WPF XAML :

<TabControl Grid.Row="1" ItemsSource="{Binding Pages.ListViewModels}" SelectedItem="{Binding Pages.Current}"  >
    <TabControl.ContentTemplate>
        <DataTemplate>
            <views:EditPageView />
        </DataTemplate>
    </TabControl.ContentTemplate>
    <TabControl.ItemTemplate>
        <DataTemplate>                                    
            <TextBlock Text="{Binding Header}"/>
        </DataTemplate>
    </TabControl.ItemTemplate>
</TabControl>

C# Codes:

public class QuestionPageSection : INotifyPropertyChanged
{
    public virtual int Id { get; set; }
    public virtual string Header { get; set; }
    private int _Order;
    public virtual int Order
    {
        get
        {
            return _Order;
        }
        set
        {
            _Order = value;
            this.RaisePropertyChanged(() => this.Order , PropertyChanged);
        }
    }
    public event PropertyChangedEventHandler  PropertyChanged;
}

I want to force TabControl to sort TabItems based on the Order property. So now I have these questoins:

Is there any way to do it declaratively?
Does TabControl have a SortColumn property?
Does TabItem have a TabOrder property?
Is there any type of collection that listen to its childs to automatically sort itself based on a property of childs??

Any other idea would be apperciated.

Rachel Rachel · Accepted Answer · 2011-09-29T15:07:35

You simply need to sort the collection that your TabControl is bound to

I've always hated the fact that ObservableCollection doesn't have a built-in Sort method, so I usually use my own custom class that inherits from ObservableCollection

public class ObservableCollectionEx<T> : ObservableCollection<T>
{
    public ObservableCollectionEx() : base() { }
    public ObservableCollectionEx(List<T> l) : base(l) { }
    public ObservableCollectionEx(IEnumerable<T> l) : base(l) { }

    #region IndexOf

    /// <summary>
    /// Returns the index of the first object which meets the specified function
    /// </summary>
    /// <param name="keySelector">A bool function to compare each Item by</param>
    /// <returns>The index of the first Item which matches the function</returns>
    public int IndexOf(Func<T, bool> compareFunction)
    {
        return Items.IndexOf(Items.FirstOrDefault(compareFunction));
    }

    #endregion

    #region Sorting

    /// <summary>
    /// Sorts the items of the collection in ascending order according to a key.
    /// </summary>
    /// <typeparam name="TKey">The type of the key returned by <paramref name="keySelector"/>.</typeparam>
    /// <param name="keySelector">A function to extract a key from an item.</param>
    public void Sort<TKey>(Func<T, TKey> keySelector)
    {
        InternalSort(Items.OrderBy(keySelector));
    }

    /// <summary>
    /// Sorts the items of the collection in descending order according to a key.
    /// </summary>
    /// <typeparam name="TKey">The type of the key returned by <paramref name="keySelector"/>.</typeparam>
    /// <param name="keySelector">A function to extract a key from an item.</param>
    public void SortDescending<TKey>(Func<T, TKey> keySelector)
    {
        InternalSort(Items.OrderByDescending(keySelector));
    }

    /// <summary>
    /// Sorts the items of the collection in ascending order according to a key.
    /// </summary>
    /// <typeparam name="TKey">The type of the key returned by <paramref name="keySelector"/>.</typeparam>
    /// <param name="keySelector">A function to extract a key from an item.</param>
    /// <param name="comparer">An <see cref="IComparer{T}"/> to compare keys.</param>
    public void Sort<TKey>(Func<T, TKey> keySelector, IComparer<TKey> comparer)
    {
        InternalSort(Items.OrderBy(keySelector, comparer));
    }

    /// <summary>
    /// Moves the items of the collection so that their orders are the same as those of the items provided.
    /// </summary>
    /// <param name="sortedItems">An <see cref="IEnumerable{T}"/> to provide item orders.</param>
    private void InternalSort(IEnumerable<T> sortedItems)
    {
        var sortedItemsList = sortedItems.ToList();

        foreach (var item in sortedItemsList)
        {
            Move(IndexOf(item), sortedItemsList.IndexOf(item));
        }
    }

    #endregion
}

I can use it like this:

ListViewModels = GetListViewModels();
ListViewModels.Sort(p => p.Order);

How to sort TabItems in the TabControl

3 Answers