Question

I am populating a treeview control, c# visual studio 8, using this code:

private TreeNode TraverseDirectory(string path)
    {
        TreeNode result = new TreeNode(path);
        foreach (var subdirectory in Directory.GetDirectories(path))
        {
            result.Nodes.Add(TraverseDirectory(subdirectory));
        }

        return result;
    }

The trouble is that if I click on, say the c:/ drive I get an error on directories that I do not have permission to read. My question is, how do I avoid showing those directories that I do not have permission for? How would I test for that and then tell the app to ignore them?

Thanks R.

Answer 1

For a simplistic approach:

TreeNode result;
try {
    string[] subdirs = Directory.GetDirectories(path);
    result = new TreeNode(path);
    foreach(string subdir in subdirs) {
        TreeNode child = TraverseDirectory(subdir);
        if(child != null) { result.Nodes.Add(child); }
    }
    return result;
} catch (FindTheSpecificException) {
    // ignore dir
    result = null;
}
return result;

personally I’d try and do some kind of lazy loading, but IIRC this involves adding dummy nodes with the standard TreeView.