Created
September 6, 2011 09:51
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ListBox などの項目のドラッグアンドドロップ移動のビヘイビア
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using System; | |
using System.Collections; | |
using System.Collections.Generic; | |
using System.Linq; | |
using System.Reactive.Disposables; | |
using System.Reactive.Linq; | |
using System.Windows; | |
using System.Windows.Controls.Primitives; | |
using System.Windows.Input; | |
using System.Windows.Interactivity; | |
using System.Windows.Media; | |
namespace Ignition.Presentation | |
{ | |
public class DragDropBehavior : Behavior<Selector> | |
{ | |
readonly CompositeDisposable observer = new CompositeDisposable(); | |
protected override void OnAttached() | |
{ | |
observer.Add(Observable.FromEvent<MouseButtonEventHandler, MouseButtonEventArgs>(_ => (sender, e) => _(e), _ => this.AssociatedObject.PreviewMouseDown += _, _ => this.AssociatedObject.PreviewMouseDown -= _) | |
.Where(_ => _.LeftButton == MouseButtonState.Pressed && this.AssociatedObject.ContainerFromElement((DependencyObject)_.OriginalSource) != null) | |
.Select(_ => _.GetPosition(this.AssociatedObject)) | |
.SelectMany(pt => Observable.FromEvent<MouseEventHandler, MouseEventArgs>(_ => (sender, e) => _(e), _ => this.AssociatedObject.PreviewMouseMove += _, _ => this.AssociatedObject.PreviewMouseMove -= _) | |
.TakeUntil(Observable.FromEvent<MouseButtonEventHandler, MouseButtonEventArgs>(_ => (sender, e) => _(e), _ => this.AssociatedObject.PreviewMouseUp += _, _ => this.AssociatedObject.PreviewMouseUp -= _)) | |
.Select(_ => new | |
{ | |
Items = this.AssociatedObject.Items.Cast<object>().Select(i => new | |
{ | |
Container = this.AssociatedObject.ItemContainerGenerator.ContainerFromItem(i), | |
Item = i | |
}).Where(i => Selector.GetIsSelected(i.Container)).Select(i => i.Item).ToArray(), | |
Vector = pt - _.GetPosition(this.AssociatedObject), | |
}) | |
.Where(_ => Math.Abs(_.Vector.X) > SystemParameters.MinimumHorizontalDragDistance || Math.Abs(_.Vector.Y) > SystemParameters.MinimumVerticalDragDistance) | |
.Take(1)) | |
.Subscribe(e => | |
{ | |
using (Observable.FromEvent<DragEventHandler, DragEventArgs>(_ => (sender, e2) => _(e2), _ => this.AssociatedObject.Drop += _, _ => this.AssociatedObject.Drop -= _) | |
.Where(_ => _.Data.GetDataPresent(typeof(DragDropInfo))) | |
.Select(_ => new | |
{ | |
EventArgs = _, | |
Data = (DragDropInfo)_.Data.GetData(typeof(DragDropInfo)), | |
}) | |
.Subscribe(p => | |
{ | |
var list = this.AssociatedObject.ItemsSource as IList ?? this.AssociatedObject.Items; | |
var item = list.Cast<object>().Select((_, i) => new | |
{ | |
Container = _ as FrameworkElement ?? (FrameworkElement)this.AssociatedObject.ItemContainerGenerator.ContainerFromIndex(i), | |
Item = _, | |
}) | |
.Where(_ => _.Container != null) | |
.LastOrDefault(_ => VisualTreeHelper.HitTest(_.Container, p.EventArgs.GetPosition(_.Container)) != null); | |
if (item == null) | |
foreach (var i in p.Data.Items) | |
{ | |
list.Remove(i); | |
list.Add(i); | |
} | |
else | |
foreach (var i in p.Data.Items.Where(_ => _ != item.Item && !object.Equals(_, item.Item))) | |
{ | |
list.Remove(i); | |
list.Insert(list.IndexOf(item.Item), i); | |
} | |
})) | |
{ | |
var ad = this.AssociatedObject.AllowDrop; | |
this.AssociatedObject.AllowDrop = true; | |
DragDrop.DoDragDrop(this.AssociatedObject, new DragDropInfo(e.Items), DragDropEffects.Move); | |
this.AssociatedObject.AllowDrop = ad; | |
} | |
})); | |
base.OnAttached(); | |
} | |
protected override void OnDetaching() | |
{ | |
observer.Dispose(); | |
base.OnDetaching(); | |
} | |
class DragDropInfo | |
{ | |
public IEnumerable<object> Items | |
{ | |
get; | |
private set; | |
} | |
public DragDropInfo(IEnumerable<object> items) | |
{ | |
this.Items = items; | |
} | |
} | |
} | |
} |
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