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using System;
using System.Linq;
using System.Collections.Generic;
using System.Windows;
using System.Windows.Media;
namespace LinqToVisualTree
{
/// <summary>
/// Adapts a DependencyObject to provide methods required for generate
/// a Linq To Tree API
/// </summary>
public class VisualTreeAdapter : ILinqTree<DependencyObject>
{
private DependencyObject _item;
public VisualTreeAdapter(DependencyObject item)
{
_item = item;
}
public IEnumerable<DependencyObject> Children()
{
int childrenCount = VisualTreeHelper.GetChildrenCount(_item);
for (int i = 0; i < childrenCount; i++)
{
yield return VisualTreeHelper.GetChild(_item, i);
}
}
public DependencyObject Parent
{
get
{
return VisualTreeHelper.GetParent(_item);
}
}
}
}
namespace LinqToVisualTree
{
/// <summary>
/// Defines an interface that must be implemented to generate the LinqToTree methods
/// </summary>
/// <typeparam name="T"></typeparam>
public interface ILinqTree<T>
{
IEnumerable<T> Children();
T Parent { get; }
}
public static class TreeExtensions
{
/// <summary>
/// Returns a collection of descendant elements.
/// </summary>
public static IEnumerable<DependencyObject> Descendants(this DependencyObject item)
{
ILinqTree<DependencyObject> adapter = new VisualTreeAdapter(item);
foreach (var child in adapter.Children())
{
yield return child;
foreach (var grandChild in child.Descendants())
{
yield return grandChild;
}
}
}
/// <summary>
/// Returns a collection containing this element and all descendant elements.
/// </summary>
public static IEnumerable<DependencyObject> DescendantsAndSelf(this DependencyObject item)
{
yield return item;
foreach (var child in item.Descendants())
{
yield return child;
}
}
/// <summary>
/// Returns a collection of ancestor elements.
/// </summary>
public static IEnumerable<DependencyObject> Ancestors(this DependencyObject item)
{
ILinqTree<DependencyObject> adapter = new VisualTreeAdapter(item);
var parent = adapter.Parent;
while (parent != null)
{
yield return parent;
adapter = new VisualTreeAdapter(parent);
parent = adapter.Parent;
}
}
/// <summary>
/// Returns a collection containing this element and all ancestor elements.
/// </summary>
public static IEnumerable<DependencyObject> AncestorsAndSelf(this DependencyObject item)
{
yield return item;
foreach (var ancestor in item.Ancestors())
{
yield return ancestor;
}
}
/// <summary>
/// Returns a collection of child elements.
/// </summary>
public static IEnumerable<DependencyObject> Elements(this DependencyObject item)
{
ILinqTree<DependencyObject> adapter = new VisualTreeAdapter(item);
foreach (var child in adapter.Children())
{
yield return child;
}
}
/// <summary>
/// Returns a collection of the sibling elements before this node, in document order.
/// </summary>
public static IEnumerable<DependencyObject> ElementsBeforeSelf(this DependencyObject item)
{
if (item.Ancestors().FirstOrDefault() == null)
yield break;
foreach (var child in item.Ancestors().First().Elements())
{
if (child.Equals(item))
break;
yield return child;
}
}
/// <summary>
/// Returns a collection of the after elements after this node, in document order.
/// </summary>
public static IEnumerable<DependencyObject> ElementsAfterSelf(this DependencyObject item)
{
if (item.Ancestors().FirstOrDefault() == null)
yield break;
bool afterSelf = false;
foreach (var child in item.Ancestors().First().Elements())
{
if (afterSelf)
yield return child;
if (child.Equals(item))
afterSelf = true;
}
}
/// <summary>
/// Returns a collection containing this element and all child elements.
/// </summary>
public static IEnumerable<DependencyObject> ElementsAndSelf(this DependencyObject item)
{
yield return item;
foreach (var child in item.Elements())
{
yield return child;
}
}
/// <summary>
/// Returns a collection of descendant elements which match the given type.
/// </summary>
public static IEnumerable<DependencyObject> Descendants<T>(this DependencyObject item)
{
return item.Descendants().Where(i => i is T).Cast<DependencyObject>();
}
/// <summary>
/// Returns a collection of the sibling elements before this node, in document order
/// which match the given type.
/// </summary>
public static IEnumerable<DependencyObject> ElementsBeforeSelf<T>(this DependencyObject item)
{
return item.ElementsBeforeSelf().Where(i => i is T).Cast<DependencyObject>();
}
/// <summary>
/// Returns a collection of the after elements after this node, in document order
/// which match the given type.
/// </summary>
public static IEnumerable<DependencyObject> ElementsAfterSelf<T>(this DependencyObject item)
{
return item.ElementsAfterSelf().Where(i => i is T).Cast<DependencyObject>();
}
/// <summary>
/// Returns a collection containing this element and all descendant elements
/// which match the given type.
/// </summary>
public static IEnumerable<DependencyObject> DescendantsAndSelf<T>(this DependencyObject item)
{
return item.DescendantsAndSelf().Where(i => i is T).Cast<DependencyObject>();
}
/// <summary>
/// Returns a collection of ancestor elements which match the given type.
/// </summary>
public static IEnumerable<DependencyObject> Ancestors<T>(this DependencyObject item)
{
return item.Ancestors().Where(i => i is T).Cast<DependencyObject>();
}
/// <summary>
/// Returns a collection containing this element and all ancestor elements
/// which match the given type.
/// </summary>
public static IEnumerable<DependencyObject> AncestorsAndSelf<T>(this DependencyObject item)
{
return item.AncestorsAndSelf().Where(i => i is T).Cast<DependencyObject>();
}
/// <summary>
/// Returns a collection of child elements which match the given type.
/// </summary>
public static IEnumerable<DependencyObject> Elements<T>(this DependencyObject item)
{
return item.Elements().Where(i => i is T).Cast<DependencyObject>();
}
/// <summary>
/// Returns a collection containing this element and all child elements.
/// which match the given type.
/// </summary>
public static IEnumerable<DependencyObject> ElementsAndSelf<T>(this DependencyObject item)
{
return item.ElementsAndSelf().Where(i => i is T).Cast<DependencyObject>();
}
}
public static class EnumerableTreeExtensions
{
/// <summary>
/// Applies the given function to each of the items in the supplied
/// IEnumerable.
/// </summary>
private static IEnumerable<DependencyObject> DrillDown(this IEnumerable<DependencyObject> items,
Func<DependencyObject, IEnumerable<DependencyObject>> function)
{
foreach (var item in items)
{
foreach (var itemChild in function(item))
{
yield return itemChild;
}
}
}
/// <summary>
/// Applies the given function to each of the items in the supplied
/// IEnumerable, which match the given type.
/// </summary>
public static IEnumerable<DependencyObject> DrillDown<T>(this IEnumerable<DependencyObject> items,
Func<DependencyObject, IEnumerable<DependencyObject>> function)
where T : DependencyObject
{
foreach (var item in items)
{
foreach (var itemChild in function(item))
{
if (itemChild is T)
{
yield return (T)itemChild;
}
}
}
}
/// <summary>
/// Returns a collection of descendant elements.
/// </summary>
public static IEnumerable<DependencyObject> Descendants(this IEnumerable<DependencyObject> items)
{
return items.DrillDown(i => i.Descendants());
}
/// <summary>
/// Returns a collection containing this element and all descendant elements.
/// </summary>
public static IEnumerable<DependencyObject> DescendantsAndSelf(this IEnumerable<DependencyObject> items)
{
return items.DrillDown(i => i.DescendantsAndSelf());
}
/// <summary>
/// Returns a collection of ancestor elements.
/// </summary>
public static IEnumerable<DependencyObject> Ancestors(this IEnumerable<DependencyObject> items)
{
return items.DrillDown(i => i.Ancestors());
}
/// <summary>
/// Returns a collection containing this element and all ancestor elements.
/// </summary>
public static IEnumerable<DependencyObject> AncestorsAndSelf(this IEnumerable<DependencyObject> items)
{
return items.DrillDown(i => i.AncestorsAndSelf());
}
/// <summary>
/// Returns a collection of child elements.
/// </summary>
public static IEnumerable<DependencyObject> Elements(this IEnumerable<DependencyObject> items)
{
return items.DrillDown(i => i.Elements());
}
/// <summary>
/// Returns a collection containing this element and all child elements.
/// </summary>
public static IEnumerable<DependencyObject> ElementsAndSelf(this IEnumerable<DependencyObject> items)
{
return items.DrillDown(i => i.ElementsAndSelf());
}
/// <summary>
/// Returns a collection of descendant elements which match the given type.
/// </summary>
public static IEnumerable<DependencyObject> Descendants<T>(this IEnumerable<DependencyObject> items)
where T : DependencyObject
{
return items.DrillDown<T>(i => i.Descendants());
}
/// <summary>
/// Returns a collection containing this element and all descendant elements.
/// which match the given type.
/// </summary>
public static IEnumerable<DependencyObject> DescendantsAndSelf<T>(this IEnumerable<DependencyObject> items)
where T : DependencyObject
{
return items.DrillDown<T>(i => i.DescendantsAndSelf());
}
/// <summary>
/// Returns a collection of ancestor elements which match the given type.
/// </summary>
public static IEnumerable<DependencyObject> Ancestors<T>(this IEnumerable<DependencyObject> items)
where T : DependencyObject
{
return items.DrillDown<T>(i => i.Ancestors());
}
/// <summary>
/// Returns a collection containing this element and all ancestor elements.
/// which match the given type.
/// </summary>
public static IEnumerable<DependencyObject> AncestorsAndSelf<T>(this IEnumerable<DependencyObject> items)
where T : DependencyObject
{
return items.DrillDown<T>(i => i.AncestorsAndSelf());
}
/// <summary>
/// Returns a collection of child elements which match the given type.
/// </summary>
public static IEnumerable<DependencyObject> Elements<T>(this IEnumerable<DependencyObject> items)
where T : DependencyObject
{
return items.DrillDown<T>(i => i.Elements());
}
/// <summary>
/// Returns a collection containing this element and all child elements.
/// which match the given type.
/// </summary>
public static IEnumerable<DependencyObject> ElementsAndSelf<T>(this IEnumerable<DependencyObject> items)
where T : DependencyObject
{
return items.DrillDown<T>(i => i.ElementsAndSelf());
}
}
}
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