c# – 检查FTP服务器上是否存在目录

public bool DirectoryExists(string directory)
    {
        bool directoryExists;

        var request = (FtpWebRequest)WebRequest.Create(directory);
        request.Method = WebRequestMethods.Ftp.ListDirectory;
        request.Credentials = new NetworkCredential("user","pass");

        try
        {
            using (request.GetResponse())
            {
                directoryExists = true;
            }
        }
        catch (WebException)
        {
            directoryExists = false;
        }

        return directoryExists;
    }

在这种情况下：

directory = @"ftp://ftp.example.com/Rubicon";

在我的服务器上,我有一个名为Rubicon1的文件夹.这使我的支票返回true.如何确保它失败,除非它完全匹配目录名称？