Recursive ContainerFromItem

2013-08-27

15360
0
C#
2013-12-12

在使用WPF的TreeView時，透過ItemContainerGenerator.ContainerFromItem找尋特定的TreeViewItem，只能找到第一層的節點。第二層以後的節點必須要透過遞迴下去找尋，像是下面這樣：

	public DependencyObject ContainerFromItemItems(Control itemsControl, object value)
	{
		var dp = itemsControl.ItemContainerGenerator.ContainerFromItem(value);

		if (dp != null)
			return dp;

		foreach (var item in itemsControl.Items)
		{
			var currentTreeViewItem = itemsControl.ItemContainerGenerator.ContainerFromItem(item);

			var childDp = ContainerFromItem(currentTreeViewItem as ItemsControl, value);

			if (childDp != null)
				return childDp;
		}
		return null;
	}

為方便後續使用，這邊筆者稍微整理了一些擴充方法，有需要的自行取用：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;

public static class ItemsControlExtension
{
	public static DependencyObject ContainerFromItem(this ItemsControl itemsControl, object value)
	{
		var dp = itemsControl.ItemContainerGenerator.ContainerFromItem(value);

		if (dp != null)
			return dp;

		foreach (var item in itemsControl.Items)
		{
			var currentTreeViewItem = itemsControl.ItemContainerGenerator.ContainerFromItem(item);

			var childDp = ContainerFromItem(currentTreeViewItem as ItemsControl, value);

			if (childDp != null)
				return childDp;
		}
		return null;
	}

	public static T ContainerFromItem<T>(this ItemsControl itemsControl, object value) where T : class
	{
		return ContainerFromItem(itemsControl, value) as T;
	}
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls.Primitives;

public static class SelectorExtension
{
	public static DependencyObject ContainerFromSelectedItem(Selector selector)
	{
		var selectedItem = selector.SelectedItem;

		if (selectedItem == null)
			return null;

		return selector.ContainerFromItem(selectedItem);
	}

	public static T ContainerFromSelectedItem<T>(Selector selector) where T : class
	{
		return ContainerFromSelectedItem(selector) as T;
	}
}

using System.Windows;
using System.Windows.Controls;

public static class TreeViewExtension
{
	public static void ClearSelection(this TreeView treeview)
	{
		var selectedItem = ContainerFromSelectedItem<TreeViewItem>(treeview);

		if (selectedItem == null) return;

		selectedItem.IsSelected = false;

	}

	public static DependencyObject ContainerFromSelectedItem(this TreeView treeview)
	{
		var selectedItem = treeview.SelectedItem;

		if (selectedItem == null)
			return null;

		return treeview.ContainerFromItem(selectedItem);
	}

	public static T ContainerFromSelectedItem<T>(this TreeView treeview) where T : class
	{
		return ContainerFromSelectedItem(treeview) as T;
	}
}

回首頁