ASP.NET でレジストリ参照２

ASP.NET でレジストリ参照を関数化しました。

<%@ PAGE LANGUAGE="C#" %>
<%@ Import Namespace="Microsoft.Win32" %>
<html>
<head>
<title>get username</title>
<style>
table{border-collapse:collapse;}
tr{vertical-align:top;}
td{border:1px solid #999;
font-family:monospace;}
</style>
<script runat="server">
void Page_Load(object sender, EventArgs e)
{
  String str_table;
  String str_result = "";
  String domain_key = "SYSTEM\\CurrentControlSet\\Services\\Tcpip\\Parameters";
  String domain_val = "Domain";
  String dn_key = "SYSTEM\\CurrentControlSet\\Services\\NTDS\\Parameters";
  String dn_val = "Root Domain";
  String no_key = "no key";
  String no_val = "no val";

  str_table = "<tr><td>"+domain_val+"</td><td>";
  if( RegistryRead(domain_key,domain_val, ref str_result) )
  {
    str_table += "成功</td><td>";
  }
  else
  {
    str_table += "失敗</td><td>";
  }
  str_table += str_result+"</td></tr>";

  str_table += "<tr><td>"+dn_val+"</td><td>";
  if( RegistryRead(dn_key,dn_val, ref str_result) )
  {
    str_table += "成功</td><td>";
  }
  else
  {
    str_table += "失敗</td><td>";
  }
  str_table += str_result+"</td></tr>";

  str_table += "<tr><td>"+no_key+"</td><td>";
  if( RegistryRead(no_key,no_val, ref str_result) )
  {
    str_table += "成功</td><td>";
  }
  else
  {
    str_table += "失敗</td><td>";
  }
  str_table += str_result+"</td></tr>";

  str_table += "<tr><td>"+no_val+"</td><td>";
  if( RegistryRead(domain_key,no_val, ref str_result) )
  {
    str_table += "成功</td><td>";
  }
  else
  {
    str_table += "失敗</td><td>";
  }
  str_table += str_result+"</td></tr>";

  lbl_result.Text = "<table>"+str_table+"</table>";
}
bool RegistryRead(String Key, String Value, ref String Result)
{
  bool ret = false;
  String no_value_text = "(no value)";
  Result = "";
  
  try
  {
    using (RegistryKey rk = Registry.LocalMachine.OpenSubKey(Key))
    {
      Result = (String)(rk.GetValue(Value,no_value_text));
      rk.Close();
      if(!Result.Equals(no_value_text)) ret = true;
    }
  }
  catch(System.Security.SecurityException se)
  {
    Result = se.Message;
  }
  catch(NullReferenceException nr)
  {
    Result = nr.Message;
  }
  return ret;
}
</script>
</head>
<body>
  <form runat="server">
  <asp:Label id="lbl_result" Text="" runat="server" />
  </form>
</body>
</html>

Domain	成功	test.lan
Root Domain	失敗	要求されたレジストリアクセスは許可されていません。
no key	失敗	オブジェクト参照がオブジェクトインスタンスに設定されていません。
no val	失敗	(no value)