我如何仅在C＃TreeView中查看包含具有ReadOnly属性的PDF的目录？

Question

我在C＃表单中有一个TreeView，并且希望它仅显示包含非只读PDF的目录。还应显示文件。

我当前的代码：

private static TreeNode CreateDirectoryNode(DirectoryInfo directoryInfo)
    {
        var directoryNode = new TreeNode(directoryInfo.Name);
        foreach (var directory in directoryInfo.GetDirectories())
            directoryNode.Nodes.Add(CreateDirectoryNode(directory));
        foreach (var file in directoryInfo.GetFiles("*.pdf"))
            directoryNode.Nodes.Add(new TreeNode(file.Name));
        return directoryNode;
    }

到目前为止我所知道的：

• 检查是否为只读((attributes & FileAttributes.ReadOnly) != FileAttributes.ReadOnly) == true
• 我知道文件可以具有以下属性：ReadOnly(R), Hidden(H), Archived(A), System(S)，但我不确定如何使用它们。

提前谢谢。

Answer 1

您的逻辑在添加目录节点时没有先检查任何读/写pdf文件是否存在缺陷。

考虑到文件夹可能包含所有只读pdf文件，而其子文件夹之一包含读/写pdf文件，仅检查当前目录中是否存在读/写pdf文件也是不够的：

pdffolder
    pdf1 (read-write)
    pdf2 (read-write)
    sub1 (folder)
        pdf3 (read-only)
        sub1-1 (folder)
            pdf4 (read-write)

在这种情况下，我们仍然希望sub1可见，而pdf3隐藏，因为我们希望sub1-1文件夹是可访问的（因为它下面有pdf4）

这是您的新方法。只有一个重大更改，即，如果该方法下及其任何子文件夹下都没有读/写pdf文件，则此方法可以返回NULL。

希望这会有所帮助。

private static TreeNode CreateDirectoryNode(DirectoryInfo directoryInfo)
{
    TreeNode directoryNode = null;

    // First, check if there are any read/write files in this folder
    // and create the directory node if yes, and add the pdf file node too.
    foreach (FileInfo file in directoryInfo.GetFiles("*.pdf"))
    {
        if (!File.GetAttributes(file.FullName).HasFlag(FileAttributes.ReadOnly))
        {
            if (directoryNode == null)
            {
                directoryNode = new TreeNode(directoryInfo.Name);
            }
            directoryNode.Nodes.Add(new TreeNode(file.Name));
        }
    }

    // There can be no writeable pdf files, but we should still check
    // the sub directories for the existence of a writeable pdf file
    // because even if this directory does not have one, a sub directory may,
    // and in that case we want that pdf file to be accessible.
    foreach (DirectoryInfo directory in directoryInfo.GetDirectories())
    {
        TreeNode subDirectoryNode = CreateDirectoryNode(directory);
        // the sub directory node could be null if there are no writable
        // pdf files directly under it. Create, if one of the sub directories
        // have one.
        if (subDirectoryNode != null)
        {
            if (directoryNode == null)
            {
                directoryNode = new TreeNode(directoryInfo.Name);
            }
            directoryNode.Nodes.Add(subDirectoryNode);
        }
    }

    // The return value is null only if neither this directory 
    // nor any of its sub directories have any writeable pdf files
    return directoryNode;
}