如何在TreeView控件中选择所有父节点(最多为根节点)? [英] How to get all parents (up to root) nodes for selected in TreeView control?

问题描述

如果我有一个TreeView(myTreeview)，如何获取所选节点的所有父节点(父节点，父母的父节点等)的列表?

If I have a TreeView (myTreeview),how can I obtain a list of all parent nodes (parent, parents of parents ect.) of selected node?

推荐答案

我建议您创建一组自己的树助手，例如，下一个针对您的问题:

I'd recomended you to create a set of your own tree helpers, for example, next one is for your problem:

    public static class TreeHelpers
    {
        public static IEnumerable<TItem> GetAncestors<TItem>(TItem item, Func<TItem, TItem> getParentFunc)
        {
            if (getParentFunc == null)
            {
                throw new ArgumentNullException("getParentFunc");
            }
            if (ReferenceEquals(item, null)) yield break;
            for (TItem curItem = getParentFunc(item); !ReferenceEquals(curItem, null); curItem = getParentFunc(curItem))
            {
                yield return curItem;
            }
        }

        //TODO: Add other methods, for example for 'prefix' children recurence enumeration
    }

用法示例(在您的情况下):

And example of usage (in your context):

        IList<TreeNode> ancestorList = TreeHelpers.GetAncestors(node, x => x.Parent).ToList();

为什么这比使用list<>.Add()更好? -因为我们可以使用惰性LINQ函数，例如.FirstOrDefault(x => ...)

Why is this better than using list<>.Add()? - because we can use lazy LINQ functions, such as .FirstOrDefault(x => ...)

P.S.要将当前"项包含到可枚举的结果中，请使用TItem curItem = item而不是TItem curItem = getParentFunc(item)

P.S. to include 'current' item into result enumerable, use TItem curItem = item, instead of TItem curItem = getParentFunc(item)

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