CollectionViewNode.cs :  » 2.6.4-mono-.net-core » System.Windows » System » Windows » Data » C# / CSharp Open Source

//
// CollectionViewNode.cs
//
// Contact:
//   Moonlight List (moonlight-list@lists.ximian.com)
//
// Copyright 2010 Novell, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

using System;
using System.ComponentModel;
using Mono;

namespace System.Windows.Data{

  class CollectionViewNode : PropertyPathNode {

    public override bool IsBroken {
      get { return Source == null; }
    }

    bool BindsDirectlyToSource {
      get; set;
    }

    bool BindsToView {
      get; set;
    }

    UnmanagedPropertyChangeHandler ViewChangedHandler {
      get; set;
    }

    public CollectionViewNode (bool bindsDirectlyToSource, bool bindsToView)
    {
      BindsDirectlyToSource = bindsDirectlyToSource;
      BindsToView = bindsToView;
      ViewChangedHandler = ViewChanged;
    }

    protected override void OnSourceChanged (object oldSource, object newSource)
    {
      CollectionViewSource source;
      base.OnSourceChanged (oldSource, newSource);

      source = oldSource as CollectionViewSource;
      if (source != null) {
        source.RemovePropertyChangedHandler (CollectionViewSource.ViewProperty, ViewChangedHandler);
        DisconnectViewHandlers (source.View);
      }

      source = newSource as CollectionViewSource;
      if (source != null) {
        source.AddPropertyChangedHandler (CollectionViewSource.ViewProperty, ViewChangedHandler);
        ConnectViewHandlers (source.View);
      }
    }

    void ConnectViewHandlers (ICollectionView view)
    {
      if (view != null)
        view.CurrentChanged += HandleSourceViewCurrentChanged;
    }

    void DisconnectViewHandlers (ICollectionView view)
    {
      if (view != null)
        view.CurrentChanged -= HandleSourceViewCurrentChanged;
    }

    void ViewChanged (IntPtr dependency_object, IntPtr propertyChangedEventArgs, ref MoonError error, IntPtr closure)
    {
      var oldValue = Mono.Value.ToObject (null, NativeMethods.property_changed_event_args_get_old_value (propertyChangedEventArgs));
      var newValue = Mono.Value.ToObject (null, NativeMethods.property_changed_event_args_get_new_value (propertyChangedEventArgs));

      DisconnectViewHandlers ((ICollectionView) oldValue);
      ConnectViewHandlers ((ICollectionView) newValue);

      HandleSourceViewCurrentChanged (this, EventArgs.Empty);
    }

    void HandleSourceViewCurrentChanged (object sender, EventArgs e)
    {
      UpdateValue ();
      if (Next != null)
        Next.SetSource (Value);
    }

    public override void SetValue (object value)
    {
      throw new System.NotImplementedException ();
    }

    public override void UpdateValue ()
    {
      // The simple case - we use the source object directly, whatever it is.
      if (BindsDirectlyToSource) {
        ValueType = Source == null ? null : Source.GetType ();
        Value = Source;
      } else {
        var usableSource = Source;
        ICollectionView view = null;
        if (Source is CollectionViewSource) {
          usableSource = null;
          view = ((CollectionViewSource) Source).View;
        } else if (Source is ICollectionView) {
          view = (ICollectionView) Source;
        }

        // If we have no ICollectionView, then use the Source directly.
        if (view == null) {
          ValueType = usableSource == null ? null : usableSource.GetType ();
          Value = usableSource;
        } else {
          // If we have an ICollectionView and the property we're binding to exists
          // on ICollectionView, we bind to the view. Otherwise we bind to its CurrentItem.
          if (BindsToView) {
            ValueType = view.GetType ();
            Value = view;
          } else {
            ValueType = view.CurrentItem == null ? null : view.CurrentItem.GetType ();
            Value = view.CurrentItem;
          }
        }
      }
    }
  }
}