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
这里有一些我经常使用的方法。
用法:
// Starts the search from thisUiElement (might be a UserContol, Window, etc..)
var combobox = thisUiElement.ChildOfType<ComboBox>();
var employeesListBox = thisUiElement.ChildOfName("EmployeesListBox");
// Starts the search from MainWindow to find the first DataGrid
var dataGrid = WpfUtils.ChildOfType<DataGrid>();
// Starts the search from MainWindow to find the all ListViews
List<ComboBox> allListViews = WpfUtils.ChildOfType<ListView>();
// Starts the search from MainWindow to find the element of name EmployeesComboBox
var combobox = WpfUtils.ChildOfName("EmployeesComboBox");
实现:
/*
using System.Collections.Generic;
using System.Windows;
using System.Windows.Media;
namespace WpfUtilities;
*/
public static class WpfUtils{
public static Window AppMainWindow =>
Application.Current?.MainWindow;
#region Find By Type
// Start the search from MainWindow, example usage: var combobox = WpfUtils.ChildOfType<ComboBox>();
public static T ChildOfType<T>() where T : DependencyObject =>
ChildOfType<T>(AppMainWindow);
/// This will return the first child of type T
public static T ChildOfType<T>(this DependencyObject parent)
where T : DependencyObject
{
if (parent == null) return null;
T child = default;
var numVisuals = VisualTreeHelper.GetChildrenCount(parent);
for (var i = 0; i < numVisuals; i++)
{
var v = VisualTreeHelper.GetChild(parent, i);
child = v as T ?? v.ChildOfType<T>();
if (child != null)
break;
}
return child;
}
// Start the search from MainWindow, example usage: List<ComboBox> comboboxes = WpfUtils.ChildOfType<ComboBox>();
public static IEnumerable<T> ChildrenOfType<T>() where T : DependencyObject =>
ChildrenOfType<T>(AppMainWindow);
/// This will not break the search when finding the first kid of type T, but it will keep searching to return all kids of type T
public static IEnumerable<T> ChildrenOfType<T>(
this DependencyObject parent) where T : DependencyObject
{
if (parent == null) yield break;
var numVisuals = VisualTreeHelper.GetChildrenCount(parent);
for (var i = 0; i < numVisuals; i++)
{
var child = VisualTreeHelper.GetChild(parent, i);
if (child is T dependencyObject)
yield return dependencyObject;
foreach (var childOfChild in child.ChildrenOfType<T>())
yield return childOfChild;
}
}
#endregion
#region Find By Name
/// If parent is null, the search will start from MainWindow, example usage: var combobox = WpfUtils.ChildOfName("EmployeesCombobox");
public static FrameworkElement ChildOfName(string childName,
DependencyObject parent = null)
{
parent ??= AppMainWindow;
object child = null;
var numVisuals = VisualTreeHelper.GetChildrenCount(parent);
for (var i = 0; i < numVisuals; i++)
{
var v = VisualTreeHelper.GetChild(parent, i);
child = v is FrameworkElement f && f.Name == childName
? f
: ChildOfName(childName, v);
if (child != null)
break;
}
return child as FrameworkElement;
}
#endregion
#region
// Yet another useful method, if you are writing code in a .xaml.cs file and you want to get the parent of a type.. example usage: this.ParentOfType<Grid>(); this.ParentOfType<UserControl>(); this.ParentOfType<Window>();
public static T ParentOfType<T>(this DependencyObject child) where T : DependencyObject
{
var parentDepObj = child;
do
{
parentDepObj = VisualTreeHelper.GetParent(parentDepObj);
if (parentDepObj is T parent) return parent;
} while (parentDepObj != null);
return null;
}
#endregion
}
其他回答
如果您希望找到特定类型的ALL控件,那么您可能也会对这个代码段感兴趣
public static IEnumerable<T> FindVisualChildren<T>(DependencyObject parent)
where T : DependencyObject
{
int childrenCount = VisualTreeHelper.GetChildrenCount(parent);
for (int i = 0; i < childrenCount; i++)
{
var child = VisualTreeHelper.GetChild(parent, i);
var childType = child as T;
if (childType != null)
{
yield return (T)child;
}
foreach (var other in FindVisualChildren<T>(child))
{
yield return other;
}
}
}
exciton80……我有一个问题,你的代码不递归通过用户控件。它击中了网格根并抛出了一个错误。我相信这能解决我的问题:
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;
if (String.Equals(childrenProperty, "Content") || String.Equals(childrenProperty, "Children"))
{
var collection = o.GetType().GetProperty(childrenProperty).GetValue(o, null);
if (collection is System.Windows.Controls.UIElementCollection) // snelson 6/6/11
{
foreach (var c in (IEnumerable)collection)
{
if (c.GetType().FullName == childType.FullName)
list.Add(c);
if (maxDepth == 0 || depth < maxDepth)
list.AddRange(RecursiveFindControls(
c, childType, depth + 1, maxDepth));
}
}
else if (collection != null && collection.GetType().BaseType.Name == "Panel") // snelson 6/6/11; added because was skipping control (e.g., System.Windows.Controls.Grid)
{
if (maxDepth == 0 || depth < maxDepth)
list.AddRange(RecursiveFindControls(
collection, childType, depth + 1, maxDepth));
}
}
}
return list.ToArray();
}
下面是一个使用灵活谓词的解决方案:
public static DependencyObject FindChild(DependencyObject parent, Func<DependencyObject, bool> predicate)
{
if (parent == null) return null;
int childrenCount = VisualTreeHelper.GetChildrenCount(parent);
for (int i = 0; i < childrenCount; i++)
{
var child = VisualTreeHelper.GetChild(parent, i);
if (predicate(child))
{
return child;
}
else
{
var foundChild = FindChild(child, predicate);
if (foundChild != null)
return foundChild;
}
}
return null;
}
例如,你可以这样称呼它:
var child = FindChild(parent, child =>
{
var textBlock = child as TextBlock;
if (textBlock != null && textBlock.Name == "MyTextBlock")
return true;
else
return false;
}) as TextBlock;
我找不到@CrimsonX或@Drew Noakes方法的控件,因为我的ControlTemplate位于一个单独的XAML文件中。 我用下面的方法找到了控件:
private Image backImage;
private void Diagram_Loaded(object sender, System.Windows.RoutedEventArgs e)
{
// here is the example of the ControlTemplate declaration
//<ControlTemplate x:Key="DiagramControlTemplate1" TargetType="{x:Type Diagram}">
var ctrlTemplate = (ControlTemplate)FindResource("DiagramControlTemplate1");
// diagram is the x:Name of TemplatedControl and, "backImage" is the name of control that I want to find.
var imageControl = ctrlTemplate.FindName("backImage", diagram);
if (imageControl != null)
{
this.backImage = (Image)imageControl;
}
}
这对我很有用。
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);
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