/// <summary>
/// Retrieves all descendant elements of the specified type.
/// </summary>
public static List <T> GetChildrenOfType <T>(this DependencyObject element, VisualTreeFindFlags findFlags) where T : class
{
var descendants = new List <T>();
ForEachChildOfType <T>(element, findFlags, (T t) =>
{
descendants.Add(t);
return(VisualTreeForEachResult.Continue);
});
return(descendants);
}
/// <summary>
/// Retrieves the first descendant element of the specified type (depth-first
/// retrieval); may return the element itself unless otherwise specified.
/// </summary>
public static T GetFirstChildOfType <T>(this DependencyObject element, VisualTreeFindFlags findFlags) where T : class
{
var tWrapper = new Wrapper <T>();
ForEachChildOfType <T>(element, findFlags, (T t) =>
{
tWrapper.Value = t;
return(VisualTreeForEachResult.Stop);
});
return(tWrapper.Value);
}
/// <summary>
/// Performs the specified operation for the ancestor element (if desired), as well as each
/// descendant of the given type in the visual tree.
/// </summary>
public static VisualTreeForEachResult ForEachChildOfType <T>(this DependencyObject element, VisualTreeFindFlags findFlags, VisualTreeForEachTypedHandler <T> handler) where T : class
{
var result = VisualTreeForEachResult.Continue;
bool skipCurrent = (findFlags & VisualTreeFindFlags.ExcludeCurrentElement) == VisualTreeFindFlags.ExcludeCurrentElement;
findFlags &= ~VisualTreeFindFlags.ExcludeCurrentElement;
T asT = null;
if (!skipCurrent)
{
// Check if the element is of the supplied type
asT = element as T;
}
if (asT != null)
{
result = handler(asT);
}
if (result == VisualTreeForEachResult.Continue)
{
var asDO = element as DependencyObject;
if (asDO != null)
{
// Walk visual child list and look for more (recurse)
int count = VisualTreeHelper.GetChildrenCount(asDO);
for (int i = 0; i < count; i++)
{
var child = VisualTreeHelper.GetChild(asDO, i);
result = ForEachChildOfType <T>(child, findFlags, handler);
if (result == VisualTreeForEachResult.Stop)
{
break;
}
}
}
}
if (result == VisualTreeForEachResult.SkipChildrenAndContinue)
{
result = VisualTreeForEachResult.Continue;
}
return(result);
}
