/// <summary>
/// Finds the child fo the givent type.
/// </summary>
/// <typeparam name="T">The typeof the child to find.</typeparam>
/// <param name="source">The source to look on.</param>
/// <param name="filter">The filter to apply to determine if the found child satisfy the requirments of the caller.</param>
/// <returns>The found child if any; otherwise null.</returns>
public static T FindChild <T>(this DependencyObject source, Predicate <T> filter)
where T : DependencyObject
{
Ensure.That(source).Named("referenceVisual").IsNotNull();
Ensure.That(filter).Named("filter").IsNotNull();
DependencyObject child = null;
var count = VisualTreeHelper.GetChildrenCount(source);
for (Int32 i = 0; i < count; i++)
{
child = VisualTreeHelper.GetChild(source, i);
if (child != null && (child.GetType() == typeof(T)) && filter(( T )child))
{
break;
}
else if (child != null)
{
child = VisualTreeCrawler.FindChild(child, filter);
if (child != null && (child.GetType() == typeof(T)) && filter(( T )child))
{
break;
}
}
}
return(child as T);
}
/// <summary>
/// Determines whether the given dependency object is child
/// of an object of the specified type T.
/// </summary>
/// <typeparam name="T">The type of the parent object.</typeparam>
/// <param name="obj">The obj to determine the parent type for.</param>
/// <returns>
/// <c>true</c> if the given dependency object is child of an object of the specified type T; otherwise, <c>false</c>.
/// </returns>
public static Boolean IsChildOfType <T>(DependencyObject obj) where T : DependencyObject
{
if (obj == null)
{
return(false);
}
if (obj is T)
{
return(true);
}
var parent = VisualTreeHelper.GetParent(obj);
return(VisualTreeCrawler.IsChildOfType <T>(parent));
}
/// <summary>
/// Finds, in the Visual Tree, the parent, of the given type T,
/// of the given dependency object that matches the given condition.
/// </summary>
/// <typeparam name="T">The type of the searched parent.</typeparam>
/// <param name="obj">The object where to start search.</param>
/// <param name="matchCondition">The match condition.</param>
/// <returns>
/// The found parent dependency object or null if none is of the given type T.
/// </returns>
public static T FindParent <T>(this DependencyObject obj, Predicate <T> matchCondition) where T : DependencyObject
{
var parent = VisualTreeHelper.GetParent(obj);
if (parent == null)
{
return(null);
}
else if (parent is T && matchCondition(( T )parent))
{
return(( T )parent);
}
else
{
return(VisualTreeCrawler.FindParent <T>(parent, matchCondition));
}
}
