使用DirectorySearcher时发生操作错误

Question

我遇到了这个错误：

  

发生操作错误

此处发生错误：

SearchResult findUser = searcher.FindOne();

完整代码：

DirectorySearcher searcher = new DirectorySearcher();

searcher.SearchScope = SearchScope.Subtree;
string UserName = Page.User.Identity.Name;
searcher.Filter = string.Format(CultureInfo.InvariantCulture, 
                                "(sAMAccountName={0})", UserName);

SearchResult findUser = searcher.FindOne();