我需要在WPF控件层次结构中搜索与给定名称或类型匹配的控件。我该怎么做呢?
当前回答
您可以使用VisualTreeHelper来查找控件。下面是一个使用VisualTreeHelper查找指定类型的父控件的方法。您也可以使用VisualTreeHelper以其他方式查找控件。
public static class UIHelper
{
/// <summary>
/// Finds a parent of a given item on the visual tree.
/// </summary>
/// <typeparam name="T">The type of the queried item.</typeparam>
/// <param name="child">A direct or indirect child of the queried item.</param>
/// <returns>The first parent item that matches the submitted type parameter.
/// If not matching item can be found, a null reference is being returned.</returns>
public static T FindVisualParent<T>(DependencyObject child)
where T : DependencyObject
{
// get parent item
DependencyObject parentObject = VisualTreeHelper.GetParent(child);
// we’ve reached the end of the tree
if (parentObject == null) return null;
// check if the parent matches the type we’re looking for
T parent = parentObject as T;
if (parent != null)
{
return parent;
}
else
{
// use recursion to proceed with next level
return FindVisualParent<T>(parentObject);
}
}
}
这样叫它:
Window owner = UIHelper.FindVisualParent<Window>(myControl);
其他回答
我编辑了CrimsonX的代码,因为它不能处理超类类型:
public static T FindChild<T>(DependencyObject depObj, string childName)
where T : DependencyObject
{
// Confirm obj is valid.
if (depObj == null) return null;
// success case
if (depObj is T && ((FrameworkElement)depObj).Name == childName)
return depObj as T;
for (int i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++)
{
DependencyObject child = VisualTreeHelper.GetChild(depObj, i);
//DFS
T obj = FindChild<T>(child, childName);
if (obj != null)
return obj;
}
return null;
}
下面是我的代码,通过类型来查找控件,同时控制我们进入层次结构的深度 (maxDepth == 0表示无限深)。
public static class FrameworkElementExtension
{
public static object[] FindControls(
this FrameworkElement f, Type childType, int maxDepth)
{
return RecursiveFindControls(f, childType, 1, maxDepth);
}
private static object[] RecursiveFindControls(
object o, Type childType, int depth, int maxDepth = 0)
{
List<object> list = new List<object>();
var attrs = o.GetType()
.GetCustomAttributes(typeof(ContentPropertyAttribute), true);
if (attrs != null && attrs.Length > 0)
{
string childrenProperty = (attrs[0] as ContentPropertyAttribute).Name;
foreach (var c in (IEnumerable)o.GetType()
.GetProperty(childrenProperty).GetValue(o, null))
{
if (c.GetType().FullName == childType.FullName)
list.Add(c);
if (maxDepth == 0 || depth < maxDepth)
list.AddRange(RecursiveFindControls(
c, childType, depth + 1, maxDepth));
}
}
return list.ToArray();
}
}
虽然我一般喜欢递归,但在c#中编程时,它不如迭代有效,所以也许下面的解决方案比John Myczek建议的更整洁?这将从给定控件搜索层次结构,以查找特定类型的祖先控件。
public static T FindVisualAncestorOfType<T>(this DependencyObject Elt)
where T : DependencyObject
{
for (DependencyObject parent = VisualTreeHelper.GetParent(Elt);
parent != null; parent = VisualTreeHelper.GetParent(parent))
{
T result = parent as T;
if (result != null)
return result;
}
return null;
}
像这样调用它来找到包含一个名为ExampleTextBox的控件的窗口:
Window window = ExampleTextBox.FindVisualAncestorOfType<Window>();
要从代码中找到给定类型的祖先,您可以使用:
[CanBeNull]
public static T FindAncestor<T>(DependencyObject d) where T : DependencyObject
{
while (true)
{
d = VisualTreeHelper.GetParent(d);
if (d == null)
return null;
var t = d as T;
if (t != null)
return t;
}
}
这个实现使用迭代而不是递归,可以稍微快一点。
如果你使用的是c# 7,这段代码可以略短:
[CanBeNull]
public static T FindAncestor<T>(DependencyObject d) where T : DependencyObject
{
while (true)
{
d = VisualTreeHelper.GetParent(d);
if (d == null)
return null;
if (d is T t)
return t;
}
}
我可能只是在重复其他人,但我确实有一段漂亮的代码,它用FindChild()方法扩展了DependencyObject类,该方法将按类型和名称获取子对象。只是包含和使用。
public static class UIChildFinder
{
public static DependencyObject FindChild(this DependencyObject reference, string childName, Type childType)
{
DependencyObject foundChild = null;
if (reference != null)
{
int childrenCount = VisualTreeHelper.GetChildrenCount(reference);
for (int i = 0; i < childrenCount; i++)
{
var child = VisualTreeHelper.GetChild(reference, i);
// If the child is not of the request child type child
if (child.GetType() != childType)
{
// recursively drill down the tree
foundChild = FindChild(child, childName, childType);
if (foundChild != null) break;
}
else if (!string.IsNullOrEmpty(childName))
{
var frameworkElement = child as FrameworkElement;
// If the child's name is set for search
if (frameworkElement != null && frameworkElement.Name == childName)
{
// if the child's name is of the request name
foundChild = child;
break;
}
}
else
{
// child element found.
foundChild = child;
break;
}
}
}
return foundChild;
}
}
希望对你有用。
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