source: branches/HeuristicLab.Problems.GrammaticalOptimization/DynamicDataDisplay/Common/IndividualArrangePanel.cs @ 12503

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Media;
using System.Collections.Specialized;
using System.Collections;
using System.ComponentModel;
using System.Windows.Controls;

namespace Microsoft.Research.DynamicDataDisplay.Common
{
  /// <summary>
  /// Represents a custom Panel, which performs Arrange of its children independently, and does not remeasure or rearrange itself or all children when one child is
  /// added or removed.
  /// Is intended to be a base class for special layout panels, in which each childr is arranged independently from each other child,
  /// e.g. panel with child's position viewport bound to a rectangle in viewport coordinates.
  /// </summary>
  public abstract class IndividualArrangePanel : Panel
  {
    private bool inBatchAdd = false;

    /// <summary>
    /// Initializes a new instance of the <see cref="IndependentArrangePanel"/> class.
    /// </summary>
    protected IndividualArrangePanel() { }

    private UIChildrenCollection children;
    /// <summary>
    /// Creates a new <see cref="T:System.Windows.Controls.UIElementCollection"/>.
    /// </summary>
    /// <param name="logicalParent">The logical parent element of the collection to be created.</param>
    /// <returns>
    /// An ordered collection of elements that have the specified logical parent.
    /// </returns>
    protected sealed override UIElementCollection CreateUIElementCollection(FrameworkElement logicalParent)
    {
      children = new UIChildrenCollection(this, logicalParent);
      children.IsAddingMany = inBatchAdd;
      return children;
    }

    public bool InBatchAdd
    {
      get { return children.IsAddingMany; }
    }

    public virtual void BeginBatchAdd()
    {
      if (children == null)
      {
        inBatchAdd = true;
        return;
      }

      children.IsAddingMany = true;
    }

    public virtual void EndBatchAdd()
    {
      children.IsAddingMany = false;
    }

    /// <summary>
    /// Called when child is added.
    /// </summary>
    /// <param name="child">The added child.</param>
    protected internal virtual void OnChildAdded(FrameworkElement child) { }

    #region Overrides

    /// <summary>
    /// Overrides <see cref="M:System.Windows.Media.Visual.GetVisualChild(System.Int32)"/>, and returns a child at the specified index from a collection of child elements.
    /// </summary>
    /// <param name="index">The zero-based index of the requested child element in the collection.</param>
    /// <returns>
    /// The requested child element. This should not return null; if the provided index is out of range, an exception is thrown.
    /// </returns>
    protected sealed override Visual GetVisualChild(int index)
    {
      return Children[index];
    }

    /// <summary>
    /// Gets the number of visual child elements within this element.
    /// </summary>
    /// <value></value>
    /// <returns>
    /// The number of visual child elements for this element.
    /// </returns>
    protected sealed override int VisualChildrenCount
    {
      get { return Children.Count; }
    }

    /// <summary>
    /// Gets an enumerator for logical child elements of this element.
    /// </summary>
    /// <value></value>
    /// <returns>
    /// An enumerator for logical child elements of this element.
    /// </returns>
    protected sealed override IEnumerator LogicalChildren
    {
      get
      {
        return Children.GetEnumerator();
      }
    }

    #endregion
  }
}