问UIAutomation找不到子节点

EN

class Program
{
    // add a COM reference to UIAutomationClient (don't use .NET legacy UIA .dll)
    private static readonly CUIAutomation8 _automation = new CUIAutomation8(); // using UIAutomationClient;

    static void Main()
    {
        var process = Process.GetProcessesByName("InetMgr").FirstOrDefault();
        if (process == null)
        {
            Console.WriteLine("InetMgr not started.");
            return;
        }

        var inetmgr = _automation.ElementFromHandle(process.MainWindowHandle);
        if (inetmgr == null)
            return;

        // note: set "Embed Interop Type" to false in UIAutomationClient reference node or redefine all UIA_* used constants manually
        // also: you *must* this program as administrator to see this panel
        var connections = inetmgr.FindFirst(TreeScope.TreeScope_Subtree,
            _automation.CreatePropertyCondition(UIA_PropertyIds.UIA_AutomationIdPropertyId, "_hierarchyPanel"));
        if (connections == null)
            return;

        var treeRoot = connections.FindFirst(TreeScope.TreeScope_Subtree,
            _automation.CreatePropertyCondition(UIA_PropertyIds.UIA_ControlTypePropertyId, UIA_ControlTypeIds.UIA_TreeItemControlTypeId));

        Dump(0, treeRoot);
    }

    static void Dump(int indent, IUIAutomationElement element)
    {
        var s = new string(' ', indent);
        Console.WriteLine(s + "name: " + element.CurrentName);

        // get expand/collapse pattern. All treeitem support that
        var expandPattern = (IUIAutomationExpandCollapsePattern)element.GetCurrentPattern(UIA_PatternIds.UIA_ExpandCollapsePatternId);
        if (expandPattern != null && expandPattern.CurrentExpandCollapseState != ExpandCollapseState.ExpandCollapseState_Expanded)
        {
            try
            {
                expandPattern.Expand();
            }
            catch
            {
                // cannot be expanded
            }
        }

        // tree can be huge,only dump 2 levels max
        if (indent > 2)
            return;

        var children = element.FindAll(TreeScope.TreeScope_Children, _automation.CreateTrueCondition());
        for (var i = 0; i < children.Length; i++)
        {
            Dump(indent + 1, children.GetElement(i));
        }
    }
}