/// <summary>
/// Finds the first child of this <see cref="DependencyObject" /> matching the specified type and satisfying a specified condition by traversing either the visual or the logical tree recursively. If no child was found, <see langword="null" /> is returned.
/// </summary>
/// <typeparam name="T">The explicit type of the children to search for.</typeparam>
/// <param name="dependencyObject">The <see cref="DependencyObject" /> to traverse the tree recursively.</param>
/// <param name="treeType">A <see cref="UITreeType" /> value indicating whether to use the <see cref="LogicalTreeHelper" /> or the <see cref="VisualTreeHelper" />.</param>
/// <param name="predicate">The <see cref="Predicate{T}" /> that determines whether the child is included in the result.</param>
/// <returns>
/// The first child of the specified type that satisfies a specified condition, depending on <paramref name="treeType" />, that can be casted to <typeparamref name="T" />. If no child was found, <see langword="null" /> is returned.
/// </returns>
public static T FindChild <T>(this DependencyObject dependencyObject, UITreeType treeType, Predicate <T> predicate) where T : DependencyObject
{
Check.ArgumentNull(dependencyObject, nameof(dependencyObject));
Check.ArgumentNull(predicate, nameof(predicate));
IEnumerable <DependencyObject> children = treeType switch
{
UITreeType.Logical => LogicalTreeHelper.GetChildren(dependencyObject).OfType <DependencyObject>(),
UITreeType.Visual => Create.Enumerable(VisualTreeHelper.GetChildrenCount(dependencyObject), i => VisualTreeHelper.GetChild(dependencyObject, i)),
_ => throw Throw.InvalidEnumArgument(nameof(treeType), treeType)
};
foreach (DependencyObject child in children)
{
if (child is T convertedChild && predicate(convertedChild))
{
return(convertedChild);
}
/// <summary>
/// Tries to find the closest parent of this <see cref="DependencyObject" /> matching the specified type and satisfying a specified condition by traversing either the visual or the logical tree.
/// </summary>
/// <typeparam name="T">The explicit type of the parent to search for.</typeparam>
/// <param name="dependencyObject">The <see cref="DependencyObject" /> to traverse the tree from.</param>
/// <param name="treeType">A <see cref="UITreeType" /> value indicating whether to use the <see cref="LogicalTreeHelper" /> or the <see cref="VisualTreeHelper" />.</param>
/// <param name="predicate">The <see cref="Predicate{T}" /> that determines whether the parent of the specified type is returned.</param>
/// <returns>
/// The closest visual or logical parent of this <see cref="DependencyObject" />, depending on <paramref name="treeType" /> and <paramref name="predicate" />, that is of type <typeparamref name="T" />, if found;
/// otherwise, <see langword="null" />.
/// </returns>
public static T FindParent <T>(this DependencyObject dependencyObject, UITreeType treeType, Predicate <T> predicate) where T : DependencyObject
{
Check.ArgumentNull(dependencyObject, nameof(dependencyObject));
if (dependencyObject is Visual)
{
DependencyObject parent = treeType switch
{
UITreeType.Logical => LogicalTreeHelper.GetParent(dependencyObject),
UITreeType.Visual => VisualTreeHelper.GetParent(dependencyObject),
_ => throw Throw.InvalidEnumArgument(nameof(treeType), treeType)
};
return(parent is T visualParent && predicate?.Invoke(visualParent) != false ? visualParent : parent?.FindParent <T>(treeType, predicate));
}
else
{
return(null);
}
}
/// <summary>
/// Finds all children of this <see cref="DependencyObject" /> matching the specified type and satisfying a specified condition by traversing either the visual or the logical tree recursively. If no children have been found, an empty array is returned.
/// </summary>
/// <typeparam name="T">The explicit type of the children to search for.</typeparam>
/// <param name="dependencyObject">The <see cref="DependencyObject" /> to traverse the tree recursively.</param>
/// <param name="treeType">A <see cref="UITreeType" /> value indicating whether to use the <see cref="LogicalTreeHelper" /> or the <see cref="VisualTreeHelper" />.</param>
/// <param name="predicate">The <see cref="Predicate{T}" /> that determines whether the child is included in the result.</param>
/// <returns>
/// An array of the specified type with all children, depending on <paramref name="treeType" /> and <paramref name="predicate" />, that can be casted to <typeparamref name="T" />. If no children have been found, an empty array is returned.
/// </returns>
public static T[] FindChildren <T>(this DependencyObject dependencyObject, UITreeType treeType, Predicate <T> predicate) where T : DependencyObject
{
Check.ArgumentNull(dependencyObject, nameof(dependencyObject));
List <T> result = new List <T>();
IEnumerable <DependencyObject> children = treeType switch
{
UITreeType.Logical => children = LogicalTreeHelper.GetChildren(dependencyObject).OfType <DependencyObject>(),
UITreeType.Visual => children = Create.Enumerable(VisualTreeHelper.GetChildrenCount(dependencyObject), i => VisualTreeHelper.GetChild(dependencyObject, i)),
_ => throw Throw.InvalidEnumArgument(nameof(treeType), treeType)
};
foreach (DependencyObject child in children)
{
if (child is T convertedChild && predicate?.Invoke(convertedChild) != false)
{
result.Add(convertedChild);
}
result.AddRange(child.FindChildren(treeType, predicate));
}
return(result.ToArray());
}
/// <summary>
/// Tries to find the closest parent of this <see cref="DependencyObject" /> matching the specified type by traversing either the visual or the logical tree.
/// </summary>
/// <typeparam name="T">The explicit type of the parent to search for.</typeparam>
/// <param name="dependencyObject">The <see cref="DependencyObject" /> to traverse the tree from.</param>
/// <param name="treeType">A <see cref="UITreeType" /> value indicating whether to use the <see cref="LogicalTreeHelper" /> or the <see cref="VisualTreeHelper" />.</param>
/// <returns>
/// The closest visual or logical parent of this <see cref="DependencyObject" />, depending on <paramref name="treeType" />, that is of type <typeparamref name="T" />, if found;
/// otherwise, <see langword="null" />.
/// </returns>
public static T FindParent <T>(this DependencyObject dependencyObject, UITreeType treeType) where T : DependencyObject
{
return(dependencyObject.FindParent <T>(treeType, null));
}
/// <summary>
/// Returns an array with all parents of this <see cref="DependencyObject" /> matching the specified type by traversing either the visual or the logical tree.
/// </summary>
/// <param name="dependencyObject">The <see cref="DependencyObject" /> to traverse the tree from.</param>
/// <param name="treeType">A <see cref="UITreeType" /> value indicating whether to use the <see cref="LogicalTreeHelper" /> or the <see cref="VisualTreeHelper" />.</param>
/// <returns>
/// An array with all parents of this <see cref="DependencyObject" />, depending on <paramref name="treeType" />.
/// </returns>
public static DependencyObject[] GetParents(this DependencyObject dependencyObject, UITreeType treeType)
{
Check.ArgumentNull(dependencyObject, nameof(dependencyObject));
List <DependencyObject> result = new List <DependencyObject>();
while (dependencyObject != null)
{
DependencyObject parent;
switch (treeType)
{
case UITreeType.Logical:
parent = LogicalTreeHelper.GetParent(dependencyObject);
break;
case UITreeType.Visual:
parent = VisualTreeHelper.GetParent(dependencyObject);
break;
default:
throw Throw.InvalidEnumArgument(nameof(treeType), treeType);
}
if (parent != null)
{
result.Add(parent);
}
dependencyObject = parent;
}
return(result.ToArray());
}
/// <summary>
/// Finds all children of this <see cref="DependencyObject" /> matching the specified type by traversing either the visual or the logical tree recursively. If no children have been found, an empty array is returned.
/// </summary>
/// <typeparam name="T">The explicit type of the children to search for.</typeparam>
/// <param name="dependencyObject">The <see cref="DependencyObject" /> to traverse the tree recursively.</param>
/// <param name="treeType">A <see cref="UITreeType" /> value indicating whether to use the <see cref="LogicalTreeHelper" /> or the <see cref="VisualTreeHelper" />.</param>
/// <returns>
/// An array of the specified type with all children, depending on <paramref name="treeType" />, that can be casted to <typeparamref name="T" />. If no children have been found, an empty array is returned.
/// </returns>
public static T[] FindChildren <T>(this DependencyObject dependencyObject, UITreeType treeType) where T : DependencyObject
{
return(dependencyObject.FindChildren <T>(treeType, null));
}
