使用 FileSystemWatcher 从 TreeView 中删除子节点，出现 "Cross-thread operation not valid" 错误

Question

设置 FileSystemWatcher 以更新 TreeView 以反映磁盘目录中的文件。它按预期触发并通过 TreeView returns 搜索正确的节点，但是当我发出 nodeToDelete.Remove() 命令时，出现以下错误：

'System.InvalidOperationException' 类型的未处理异常发生在 System.Windows.Forms.dll

附加信息：跨线程操作无效：控制“_tvwFiles”从创建它的线程以外的线程访问。

我没有意识到我使用了多个线程。关于如何解决这个问题的任何建议？或者也许是一种不同的方式来访问子节点以将其删除？

代码如下：

using System;
using System.IO;
using System.Windows.Forms;

namespace WaveManager
{
    public partial class FileViewControl : UserControl
    {
        public FileViewControl()
        {
            InitializeComponent();
        }

        private FileSystemWatcher _watcher;
        private const string path = @"c:\temp";

        public void OnWaveOpen(string fileName)
        {
        string filePath = Path.GetDirectoryName(fileName);

        TreeNode folderNode;
        _tvwFiles.ImageIndex = 0;
        _tvwFiles.SelectedImageIndex = 0;
        DirectoryInfo directoryInfo = new DirectoryInfo(filePath);
        //folderNode = new TreeNode(directoryInfo.Name);
        folderNode = new TreeNode(filePath);
        folderNode.Tag = directoryInfo;

        //Getfiles
        TreeNode waveNode;

        foreach (FileInfo wavefile in directoryInfo.GetFiles("*.wav"))
        {
            waveNode = new TreeNode(wavefile.Name, 1, 1);
            waveNode.Name = waveNode.Text;
            waveNode.Tag = wavefile;
            folderNode.Nodes.Add(waveNode);
            }
            _tvwFiles.Nodes.Add(folderNode);

            _tvwFiles.ExpandAll();
        }

        private void OnLoad(object sender, System.EventArgs e)
        {
            if (DesignMode)
                return;
            _tvwFiles.ExpandAll();              
            _watcher = new FileSystemWatcher(path);
            _watcher.EnableRaisingEvents = true;
            _watcher.Deleted += OnFileDeleted;

        }

        private TreeNode FindNodeByTagText(String s, TreeNodeCollection nodes)
        {
            foreach (TreeNode node in nodes)
            {
                if (node.Tag.ToString() == s)
                    return node;

                TreeNode n = FindNodeByTagText(s, node.Nodes);
                if (n != null)
                    return n;
            }

            return null;
        }

        void OnFileDeleted(object sender, FileSystemEventArgs e)
        {
            string fn = Path.GetFileName(e.FullPath);
            TreeNode nodeToDelete = FindNodeByTagText(fn, _tvwFiles.Nodes);
            nodeToDelete.Remove();
        }
    }
}

如有任何想法，我们将不胜感激。谢谢！

Answer 1

我记得（我可能弄错了，现在无法检查）FileSystemWatcher 在内部使用 ThreadPool。也许这就是你得到例外的原因。

尝试设置

_watcher.SynchronizingObject = this;

使用 FileSystemWatcher 从 TreeView 中删除子节点，出现 "Cross-thread operation not valid" 错误

Using FileSystemWatcher to delete Childnode from TreeView, getting "Cross-thread operation not valid" error

.net

c#

treeview

multithreading

children