Registry.Localmachine以字符串形式获取值

Question

我现在有此代码。

string uninstallKey = @"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall";
        using (RegistryKey rk = Registry.LocalMachine.OpenSubKey(uninstallKey))
        {
            foreach (string skName in rk.GetSubKeyNames())
            {
                using (RegistryKey sk = rk.OpenSubKey(skName))
                {
                    try
                    {
                        var displayName = sk.GetValue("DisplayName") as string;
                        if (displayName.Equals("TimeKeeper"))
                        {
                            keyName = skName;
                        }
                    }
                    catch (Exception e) { }
                }
            }
        }

但是我一直在获取System.NullReferenceException。但是，如果我尝试从当前用户注册表中获取值，则不会出现任何错误。有人知道如何解决此问题吗？