Code:
/ 4.0 / 4.0 / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / cdf / src / NetFx40 / Tools / System.Activities.Presentation / System / Activities / Presentation / Base / Core / Internal / PropertyEditing / VisualTreeUtils.cs / 1305376 / VisualTreeUtils.cs
//----------------------------------------------------------------
// Copyright (c) Microsoft Corporation. All rights reserved.
//---------------------------------------------------------------
namespace System.Activities.Presentation.Internal.PropertyEditing
{
using System;
using System.Collections;
using System.Diagnostics.CodeAnalysis;
using System.Windows;
using System.Windows.Media;
using System.Windows.Media.Media3D;
using System.Collections.Generic;
//
// Collection of simple utilities that deal with the VisualTree
//
internal static class VisualTreeUtils
{
// The depth of the visual tree we explore in looking for templated children
// (see GetTemplateChild<>())
private const int MaxSearchDepth = 5;
// The maxium wpf visual tree depth
// this value should be kept in [....] with WPF's limit
private const int MaxAllowedTreeDepth = 250;
//
// Examines the visual children of the given element and returns the one
// with the specified name and type, if one exists
//
// Type of child to look for
// Container to look in
// Name to look for
// The specified named child if found, null otherwise
public static T GetNamedChild(DependencyObject container, string name)
where T : FrameworkElement
{
return GetNamedChild(container, name, 0);
}
//
// Examines the visual children of the given element and returns the one
// with the specified name and type, if one exists
//
// Type of child to look for
// Container to look in
// Name to look for
// Visual depth to search in. Default is 0.
// The specified named child if found, null otherwise
public static T GetNamedChild(DependencyObject container, string name, int searchDepth)
where T : FrameworkElement
{
if (container == null || string.IsNullOrEmpty(name) || searchDepth < 0)
{
return null;
}
if (container is T && string.Equals( name, ((T)container).Name))
{
return (T)container;
}
int childCount = VisualTreeHelper.GetChildrenCount(container);
if (childCount == 0)
{
return null;
}
// Look for the first child that matches
for (int index = 0; index < childCount; index++)
{
FrameworkElement child = VisualTreeHelper.GetChild(container, index) as FrameworkElement;
if (child == null)
{
continue;
}
// Search recursively until we reach the requested search depth
T namedChild =
(child.FindName(name) as T) ??
(searchDepth > 0 ? GetNamedChild(child, name, searchDepth - 1) : null);
if (namedChild != null)
{
return namedChild;
}
}
return null;
}
//
// Helper method that goes down the first-child visual tree and looks for the visual element of the
// specified type. Useful for when you have one control that is templated to look like another
// and you need to get to the template instance itself.
//
// Type of the visual template to look for
// Element to start from
// The first matching instance in the visual tree of first children, null otherwise
public static T GetTemplateChild(DependencyObject element) where T : DependencyObject
{
int availableSearchDepth = MaxSearchDepth;
while (availableSearchDepth > 0 && element != null)
{
int childrenCount = VisualTreeHelper.GetChildrenCount(element);
if (childrenCount < 1)
{
return null;
}
// Just worry about the first child, since we are looking for a template control,
// not a complicated visual tree
//
element = VisualTreeHelper.GetChild(element, 0);
T childAsT = element as T;
if (childAsT != null)
{
return childAsT;
}
availableSearchDepth--;
}
return null;
}
//
// Goes up the visual tree, looking for an ancestor of the specified Type
//
// Type to look for
// Starting point
// Visual ancestor, if any, of the specified starting point and Type
[SuppressMessage("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")]
public static T FindVisualAncestor(DependencyObject child) where T : DependencyObject
{
if (child == null)
{
return null;
}
do
{
child = VisualTreeHelper.GetParent(child);
}
while (child != null && !typeof(T).IsAssignableFrom(child.GetType()));
return child as T;
}
//
// Recursively looks through all the children and looks for and returns the first
// element with IsFocusable set to true.
//
// Starting point for the search
// Type of child to look for
// The first focusable child of the specified Type, null otherwise.
public static T FindFocusableElement(T reference) where T : UIElement
{
if (reference == null || (reference.Focusable && reference.Visibility == Visibility.Visible))
{
return reference;
}
int childCount = VisualTreeHelper.GetChildrenCount(reference);
for (int i = 0; i < childCount; i++)
{
T child = VisualTreeHelper.GetChild(reference, i) as T;
if (child == null)
{
continue;
}
if (child.Visibility != Visibility.Visible)
{
continue;
}
if (child.Focusable)
{
return child;
}
child = FindFocusableElement(child);
if (child != null)
{
return child;
}
}
return null;
}
//
// Walks up the parent tree and returns the first
// element with IsFocusable set to true.
//
// Starting point for the search
// Type of parent to look for
// The first focusable parent of the specified Type, null otherwise.
public static T FindFocusableParent(UIElement reference) where T : UIElement
{
if (null != reference)
{
UIElement parent = VisualTreeHelper.GetParent(reference) as UIElement;
while (null != parent)
{
if (parent.Visibility == Visibility.Visible && parent is T && parent.Focusable)
{
return parent as T;
}
parent = VisualTreeHelper.GetParent(parent) as UIElement;
}
}
return null;
}
//
// Helper method identical to VisualTreeHelper.GetParent() but that also returns the index of the given child
// with respect to any of its visual siblings
//
// Child to examine
// Total number of children that the specified child's parent has
// Index of the specified child in the parent's visual children array
// Visual parent of the specified child, if any
public static DependencyObject GetIndexedVisualParent(DependencyObject child, out int childrenCount, out int childIndex)
{
childrenCount = 0;
DependencyObject parent = VisualTreeHelper.GetParent(child);
if (parent != null)
{
childrenCount = VisualTreeHelper.GetChildrenCount(parent);
for (childIndex = 0; childIndex < childrenCount; childIndex++)
{
if (child.Equals(VisualTreeHelper.GetChild(parent, childIndex)))
{
return parent;
}
}
}
childIndex = -1;
return null;
}
//
// Helper method that goes up the visual tree checking the visibility flag of the specified element
// and all its parents. If an invisible parent is found, the method return false. Otherwise it returns
// true.
//
// Element to check
// True if the specified element and all of its visual parents are visible,
// false otherwise.
public static bool IsVisible(UIElement element)
{
UIElement parent = element;
while (parent != null)
{
if (parent.Visibility != Visibility.Visible)
{
return false;
}
parent = VisualTreeHelper.GetParent(parent) as UIElement;
}
return true;
}
///
/// Helper method that trasverse the visual tree checking for immediate parent of specified type that has children
/// that is too deep for WPF visual tree
///
/// The type of parent to look for
/// The root element to start checking
/// PrunVisualTree(Visual root) where T : DependencyObject
{
HashSet deepElements = new HashSet();
Stack stack = new Stack();
VisualState currentObject = new VisualState(root, GetTreeDepth(root));
stack.Push(currentObject);
int totalChildCount = 0;
Visual child;
T violatingParent;
//doing a depth first walk of the visual tree.
while (stack.Count > 0)
{
currentObject = stack.Pop();
// currentObject.Depth + 1 is the children's depth
// if it's too deep, we would try to find the parent and stop traversing
// this node further
if (currentObject.Depth + 1 >= MaxAllowedTreeDepth)
{
violatingParent = currentObject.Visual as T;
if (violatingParent != null)
{
deepElements.Add(violatingParent);
}
else
{
violatingParent = FindVisualAncestor(currentObject.Visual);
if (violatingParent != null)
{
deepElements.Add(violatingParent);
}
}
}
else // continue the depth first traversal
{
totalChildCount = VisualTreeHelper.GetChildrenCount(currentObject.Visual);
for (int i = 0; i < totalChildCount; i++)
{
child = VisualTreeHelper.GetChild(currentObject.Visual, i) as Visual;
if (child != null)
{
stack.Push(new VisualState(child, currentObject.Depth + 1));
}
}
}
}
return deepElements;
}
//find the depth of an DependencyObject
public static uint GetTreeDepth(DependencyObject element)
{
uint depth = 0;
while (element != null)
{
depth++;
if (element is Visual || element is Visual3D)
{
element = VisualTreeHelper.GetParent(element);
}
else
{
element = LogicalTreeHelper.GetParent(element);
}
}
return depth;
}
private class VisualState
{
internal Visual Visual { get; set; }
internal uint Depth { get; set; }
internal VisualState(Visual visual, uint depth)
{
this.Visual = visual;
this.Depth = depth;
}
}
}
}
// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
//----------------------------------------------------------------
// Copyright (c) Microsoft Corporation. All rights reserved.
//---------------------------------------------------------------
namespace System.Activities.Presentation.Internal.PropertyEditing
{
using System;
using System.Collections;
using System.Diagnostics.CodeAnalysis;
using System.Windows;
using System.Windows.Media;
using System.Windows.Media.Media3D;
using System.Collections.Generic;
//
// Collection of simple utilities that deal with the VisualTree
//
internal static class VisualTreeUtils
{
// The depth of the visual tree we explore in looking for templated children
// (see GetTemplateChild<>())
private const int MaxSearchDepth = 5;
// The maxium wpf visual tree depth
// this value should be kept in [....] with WPF's limit
private const int MaxAllowedTreeDepth = 250;
//
// Examines the visual children of the given element and returns the one
// with the specified name and type, if one exists
//
// Type of child to look for
// Container to look in
// Name to look for
// The specified named child if found, null otherwise
public static T GetNamedChild(DependencyObject container, string name)
where T : FrameworkElement
{
return GetNamedChild(container, name, 0);
}
//
// Examines the visual children of the given element and returns the one
// with the specified name and type, if one exists
//
// Type of child to look for
// Container to look in
// Name to look for
// Visual depth to search in. Default is 0.
// The specified named child if found, null otherwise
public static T GetNamedChild(DependencyObject container, string name, int searchDepth)
where T : FrameworkElement
{
if (container == null || string.IsNullOrEmpty(name) || searchDepth < 0)
{
return null;
}
if (container is T && string.Equals( name, ((T)container).Name))
{
return (T)container;
}
int childCount = VisualTreeHelper.GetChildrenCount(container);
if (childCount == 0)
{
return null;
}
// Look for the first child that matches
for (int index = 0; index < childCount; index++)
{
FrameworkElement child = VisualTreeHelper.GetChild(container, index) as FrameworkElement;
if (child == null)
{
continue;
}
// Search recursively until we reach the requested search depth
T namedChild =
(child.FindName(name) as T) ??
(searchDepth > 0 ? GetNamedChild(child, name, searchDepth - 1) : null);
if (namedChild != null)
{
return namedChild;
}
}
return null;
}
//
// Helper method that goes down the first-child visual tree and looks for the visual element of the
// specified type. Useful for when you have one control that is templated to look like another
// and you need to get to the template instance itself.
//
// Type of the visual template to look for
// Element to start from
// The first matching instance in the visual tree of first children, null otherwise
public static T GetTemplateChild(DependencyObject element) where T : DependencyObject
{
int availableSearchDepth = MaxSearchDepth;
while (availableSearchDepth > 0 && element != null)
{
int childrenCount = VisualTreeHelper.GetChildrenCount(element);
if (childrenCount < 1)
{
return null;
}
// Just worry about the first child, since we are looking for a template control,
// not a complicated visual tree
//
element = VisualTreeHelper.GetChild(element, 0);
T childAsT = element as T;
if (childAsT != null)
{
return childAsT;
}
availableSearchDepth--;
}
return null;
}
//
// Goes up the visual tree, looking for an ancestor of the specified Type
//
// Type to look for
// Starting point
// Visual ancestor, if any, of the specified starting point and Type
[SuppressMessage("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")]
public static T FindVisualAncestor(DependencyObject child) where T : DependencyObject
{
if (child == null)
{
return null;
}
do
{
child = VisualTreeHelper.GetParent(child);
}
while (child != null && !typeof(T).IsAssignableFrom(child.GetType()));
return child as T;
}
//
// Recursively looks through all the children and looks for and returns the first
// element with IsFocusable set to true.
//
// Starting point for the search
// Type of child to look for
// The first focusable child of the specified Type, null otherwise.
public static T FindFocusableElement(T reference) where T : UIElement
{
if (reference == null || (reference.Focusable && reference.Visibility == Visibility.Visible))
{
return reference;
}
int childCount = VisualTreeHelper.GetChildrenCount(reference);
for (int i = 0; i < childCount; i++)
{
T child = VisualTreeHelper.GetChild(reference, i) as T;
if (child == null)
{
continue;
}
if (child.Visibility != Visibility.Visible)
{
continue;
}
if (child.Focusable)
{
return child;
}
child = FindFocusableElement(child);
if (child != null)
{
return child;
}
}
return null;
}
//
// Walks up the parent tree and returns the first
// element with IsFocusable set to true.
//
// Starting point for the search
// Type of parent to look for
// The first focusable parent of the specified Type, null otherwise.
public static T FindFocusableParent(UIElement reference) where T : UIElement
{
if (null != reference)
{
UIElement parent = VisualTreeHelper.GetParent(reference) as UIElement;
while (null != parent)
{
if (parent.Visibility == Visibility.Visible && parent is T && parent.Focusable)
{
return parent as T;
}
parent = VisualTreeHelper.GetParent(parent) as UIElement;
}
}
return null;
}
//
// Helper method identical to VisualTreeHelper.GetParent() but that also returns the index of the given child
// with respect to any of its visual siblings
//
// Child to examine
// Total number of children that the specified child's parent has
// Index of the specified child in the parent's visual children array
// Visual parent of the specified child, if any
public static DependencyObject GetIndexedVisualParent(DependencyObject child, out int childrenCount, out int childIndex)
{
childrenCount = 0;
DependencyObject parent = VisualTreeHelper.GetParent(child);
if (parent != null)
{
childrenCount = VisualTreeHelper.GetChildrenCount(parent);
for (childIndex = 0; childIndex < childrenCount; childIndex++)
{
if (child.Equals(VisualTreeHelper.GetChild(parent, childIndex)))
{
return parent;
}
}
}
childIndex = -1;
return null;
}
//
// Helper method that goes up the visual tree checking the visibility flag of the specified element
// and all its parents. If an invisible parent is found, the method return false. Otherwise it returns
// true.
//
// Element to check
// True if the specified element and all of its visual parents are visible,
// false otherwise.
public static bool IsVisible(UIElement element)
{
UIElement parent = element;
while (parent != null)
{
if (parent.Visibility != Visibility.Visible)
{
return false;
}
parent = VisualTreeHelper.GetParent(parent) as UIElement;
}
return true;
}
///
/// Helper method that trasverse the visual tree checking for immediate parent of specified type that has children
/// that is too deep for WPF visual tree
///
/// The type of parent to look for
/// The root element to start checking
/// PrunVisualTree(Visual root) where T : DependencyObject
{
HashSet deepElements = new HashSet();
Stack stack = new Stack();
VisualState currentObject = new VisualState(root, GetTreeDepth(root));
stack.Push(currentObject);
int totalChildCount = 0;
Visual child;
T violatingParent;
//doing a depth first walk of the visual tree.
while (stack.Count > 0)
{
currentObject = stack.Pop();
// currentObject.Depth + 1 is the children's depth
// if it's too deep, we would try to find the parent and stop traversing
// this node further
if (currentObject.Depth + 1 >= MaxAllowedTreeDepth)
{
violatingParent = currentObject.Visual as T;
if (violatingParent != null)
{
deepElements.Add(violatingParent);
}
else
{
violatingParent = FindVisualAncestor(currentObject.Visual);
if (violatingParent != null)
{
deepElements.Add(violatingParent);
}
}
}
else // continue the depth first traversal
{
totalChildCount = VisualTreeHelper.GetChildrenCount(currentObject.Visual);
for (int i = 0; i < totalChildCount; i++)
{
child = VisualTreeHelper.GetChild(currentObject.Visual, i) as Visual;
if (child != null)
{
stack.Push(new VisualState(child, currentObject.Depth + 1));
}
}
}
}
return deepElements;
}
//find the depth of an DependencyObject
public static uint GetTreeDepth(DependencyObject element)
{
uint depth = 0;
while (element != null)
{
depth++;
if (element is Visual || element is Visual3D)
{
element = VisualTreeHelper.GetParent(element);
}
else
{
element = LogicalTreeHelper.GetParent(element);
}
}
return depth;
}
private class VisualState
{
internal Visual Visual { get; set; }
internal uint Depth { get; set; }
internal VisualState(Visual visual, uint depth)
{
this.Visual = visual;
this.Depth = depth;
}
}
}
}
// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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