如何有效地删除一个TreeView选中的项目？ [英] How to Efficiently Delete Checked Items from a TreeView?

问题描述

怎么能够通过一个TreeView的所有节点很容易重复，审视自己的.Checked属性，然后删除所有选中的节点？

How can one easily iterate through all nodes in a TreeView, examine their .Checked property and then delete all checked nodes?

这看起来非常简单，但你不应该修改通过其进行迭代的集合，消除了foreach循环的可能性。 （该.Nodes.Remove呼叫被修改的集合。）如果此尝试，其效果是，只有大约一半的.Checked节点被去除。

It seems straightforward, but you aren't supposed to modify a collection through which you are iterating, eliminating the possibility of a "foreach" loop. (The .Nodes.Remove call is modifying the collection.) If this is attempted, the effect is that only about half of the .Checked nodes are removed.

即使如果一个人使用两遍：第一创建临时索引的列表，然后在第二遍中除去由指数 - 索引会改变在每次除去，伤病退役索引列表的完整性。

Even if one were to use two passes: first creating a list of temporary indexes, and then removing by index on the second pass -- the indexes would change upon each removal, invaliding the integrity of the index list.

那么，什么是最有效的方式做到这一点？

So, what is the most efficient way to do this?

下面是code，看起来很不错的例子，但实际上只删除大约一半的.Checked节点：

Here is an example of code that looks good, but actually only removes about half of the .Checked nodes.:

            foreach (TreeNode parent in treeView.Nodes)
            {
                if (parent.Checked)
                {
                    treeView.Nodes.Remove(parent);
                }
                else
                {
                    foreach (TreeNode child in parent.Nodes)
                    {
                        if (child.Checked) parent.Nodes.Remove(child);
                    }
                }
            }

（是的，目的只是从一棵树是两层深修剪的节点。）

(Yes, the intention is only to prune nodes from a tree that is two levels deep.)

推荐答案

这将删除节点列举它们后，可以递归地用于n层节点。

This will remove the nodes after enumerating them, and can be used recursively for n-tiers of nodes.

void RemoveCheckedNodes(TreeNodeCollection nodes)
{
    List<TreeNode> checkedNodes = new List<TreeNode>();

    foreach (TreeNode node in nodes)
    {
        if (node.Checked)
        {
            checkedNodes.Add(node);
        }
        else
        {
            RemoveCheckedNodes(nodes.ChildNodes);
        }
    }

    foreach (TreeNode checkedNode in checkedNodes)
    {
        nodes.Remove(checkedNode);
    }
}

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