wpf - 如何按名称或类型查找 WPF 控件？

Question

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。我怎样才能做到这一点？

Answer 1

我将 John Myczek 使用的模板格式与上面的 Tri Q 算法结合起来，创建了一个可用于任何父级的 findChild 算法。请记住，向下递归搜索树可能是一个漫长的过程。我只在 WPF 应用程序上抽查过这一点，请评论您可能发现的任何错误，我将更正我的代码。

WPF Snoop是查看可视化树的有用工具 - 我强烈建议在测试或使用此算法检查您的工作时使用它。

Tri Q 的算法存在一个小错误。找到子项后，如果 ChildrenCount > 1 并且我们再次迭代，我们可以覆盖正确找到的子项。因此，我在代码中添加了一个 if (foundChild != null) break; 来处理这种情况。

/// <summary>
/// Finds a Child of a given item in the visual tree. 
/// </summary>
/// <param name="parent">A direct parent of the queried item.</param>
/// <typeparam name="T">The type of the queried item.</typeparam>
/// <param name="childName">x:Name or Name of child. </param>
/// <returns>The first parent item that matches the submitted type parameter. 
/// If not matching item can be found, 
/// a null parent is being returned.</returns>
public static T FindChild<T>(DependencyObject parent, string childName)
   where T : DependencyObject
{    
  // Confirm parent and childName are valid. 
  if (parent == null) return null;

  T foundChild = null;

  int childrenCount = VisualTreeHelper.GetChildrenCount(parent);
  for (int i = 0; i < childrenCount; i++)
  {
    var child = VisualTreeHelper.GetChild(parent, i);
    // If the child is not of the request child type child
    T childType = child as T;
    if (childType == null)
    {
      // recursively drill down the tree
      foundChild = FindChild<T>(child, childName);

      // If the child is found, break so we do not overwrite the found child. 
      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 = (T)child;
        break;
      }
    }
    else
    {
      // child element found.
      foundChild = (T)child;
      break;
    }
  }

  return foundChild;
}

这样调用它:

TextBox foundTextBox = 
   UIHelper.FindChild<TextBox>(Application.Current.MainWindow, "myTextBoxName");

注意Application.Current.MainWindow可以是任何父窗口。