我有一个带有Order属性的类型Page的集合，我将TabControl的ItemsSource属性设置为ObservableCollection。每当我更改实体的Order属性时我需要什么 相关的TabItem位于正确的位置。
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＃代码：
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;
}
我想强制TabControl根据Order属性对TabItems进行排序。所以现在我有了这些任务：
任何其他想法都会被贬低。
答案 0 :(得分：1)
您可以使用CollectionViewSource在UI端对ObservableCollection进行排序。以下是一个示例链接：http://msdn.microsoft.com/en-us/library/ms742542.aspx
答案 1 :(得分：1)
您只需要对TabControl绑定的集合进行排序
我一直很讨厌ObservableCollection没有内置Sort方法的事实，因此我通常使用自己的自定义类继承自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
}
我可以这样使用它：
ListViewModels = GetListViewModels();
ListViewModels.Sort(p => p.Order);
答案 2 :(得分：0)
感谢Rachel，你的解决方案给了我线索，但你的解决方案仍然是一个答案，因为每当我更改Order属性时我都可以手动调用Sort方法，但我想让它自动化。所以我最终得到了代码的动态版本。
根据Rachel，我接触了这个解决方案。
public class ObservableCollectionEx<T> : ObservableCollection<T>
{
public ObservableCollectionEx() : base() { }
public ObservableCollectionEx(List<T> l) : base(l) { }
public ObservableCollectionEx(IEnumerable<T> l) : base(l) { }
Func<IEnumerable<T>,IEnumerable<T>> sortFunction;
Action reset;
#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 IndexOf
#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 SetSort<TKey>(Func<T , TKey> keySelector)
{
sortFunction = list => list.OrderBy(keySelector);
InternalSort();
reset = () => SetSort(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 SetSortDescending<TKey>(Func<T , TKey> keySelector)
{
sortFunction = list => list.OrderByDescending(keySelector);
InternalSort();
reset = () => SetSortDescending(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 SetSort<TKey>(Func<T , TKey> keySelector , IComparer<TKey> comparer)
{
sortFunction = list => list.OrderBy(keySelector , comparer);
InternalSort();
reset = () => SetSort(keySelector , comparer);
}
/// <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>
/// <param name="comparer">An <see cref="IComparer{T}"/> to compare keys.</param>
public void SetSortDescending<TKey>(Func<T , TKey> keySelector , IComparer<TKey> comparer)
{
sortFunction = list => list.OrderByDescending(keySelector , comparer);
InternalSort();
reset = () => SetSortDescending(keySelector , comparer);
}
/// <summary>
/// Moves the items of the collection so that their orders are the same as those of the items provided.
/// </summary>
private void InternalSort()
{
UpdateTracking(null , Items.ToList());
}
private void MoveItemToItsLocation(T item)
{
var sortListCache = sortFunction(Items).ToList();
Move(IndexOf(item) , sortListCache.IndexOf(item));
}
#endregion Sorting
public void UpdateTracking(IEnumerable<T> oldItems , IEnumerable<T> newItems)
{
if (sortFunction == null) return;
PropertyChangedEventHandler changeTracker = (o , change) => { MoveItemToItsLocation((T)o); };
Action<T> attachChangeTracker = o => o.ExecuteOnCast<INotifyPropertyChanged>(x => x.PropertyChanged += changeTracker);
Action<T> detachChangeTracker = o => o.ExecuteOnCast<INotifyPropertyChanged>(x => x.PropertyChanged -= changeTracker);
var greeting = new[] { attachChangeTracker , MoveItemToItsLocation };
var farwell = new[] { detachChangeTracker };
oldItems.ForEach(detachChangeTracker);
newItems.ForEach(attachChangeTracker , MoveItemToItsLocation);
}
protected override void OnCollectionChanged(NotifyCollectionChangedEventArgs e)
{
base.OnCollectionChanged(e);
switch (e.Action) {
case NotifyCollectionChangedAction.Add:
case NotifyCollectionChangedAction.Remove:
case NotifyCollectionChangedAction.Replace:
UpdateTracking(e.OldItems.SafeGet(x => x.Cast<T>()) , e.NewItems.SafeGet(x => x.Cast<T>()));
break;
case NotifyCollectionChangedAction.Reset:
UpdateTracking(Items.ToList() , null);
if (reset != null)
reset();
break;
default:
break;
}
}
}
我只做了一点改动，使其遵循底层集合中的更改，因此在对底层集合或底层集合中的任何元素进行任何更改后，它将自动排序。