System.Net.SocketPermission.ParseAddXmlElement C# (CSharp) Method

        private static void ParseAddXmlElement(SecurityElement et, ArrayList listToAdd, string accessStr) {

            foreach(SecurityElement uriElem in et.Children) {
                if (uriElem.Tag.Equals("ENDPOINT")) {
                    Hashtable attributes = uriElem.Attributes;
                    string tmpStr;

                    try {
                        tmpStr = attributes["host"] as string;
                    }
                    catch{
                        tmpStr = null;
                    }

                    if (tmpStr == null) {
                        throw new ArgumentNullException(accessStr + "host");
                    }
                    string host = tmpStr;

                    try {
                        tmpStr = attributes["transport"] as string;
                    }
                    catch{
                        tmpStr = null;
                    }
                    if (tmpStr == null) {
                        throw new ArgumentNullException(accessStr + "transport");
                    }
                    TransportType transport;
                    try {
                        transport = (TransportType) Enum.Parse(typeof(TransportType), tmpStr, true);
                    }
                    catch (Exception exception) {
                        if (exception is ThreadAbortException || exception is StackOverflowException || exception is OutOfMemoryException) {                                       
		                    throw;
	                    }
                        throw new ArgumentException(accessStr + "transport", exception);
                    }
                    catch {
                        throw new ArgumentException(accessStr + "transport", new Exception(SR.GetString(SR.net_nonClsCompliantException)));
                    }

                    try {
                        tmpStr = attributes["port"] as string;
                    }
                    catch{
                        tmpStr = null;
                    }
                    if (tmpStr == null) {
                        throw new  ArgumentNullException(accessStr + "port");
                    }
                    if (string.Compare(tmpStr, "All", StringComparison.OrdinalIgnoreCase ) == 0) {
                        tmpStr = "-1";
                    }
                    int port;
                    try {
                        port = Int32.Parse(tmpStr, NumberFormatInfo.InvariantInfo);
                    }
                    catch (Exception exception) {
                        if (exception is ThreadAbortException || exception is StackOverflowException || exception is OutOfMemoryException) {                                       
		                    throw;
	                    }
                        throw new ArgumentException(SR.GetString(SR.net_perm_invalid_val, accessStr + "port", tmpStr), exception);
                    }
                    catch {
                        throw new ArgumentException(SR.GetString(SR.net_perm_invalid_val, accessStr + "port", tmpStr), new Exception(SR.GetString(SR.net_nonClsCompliantException)));
                    }

                    if (!ValidationHelper.ValidateTcpPort(port) && port != SocketPermission.AllPorts) {
                        throw new ArgumentOutOfRangeException(SR.GetString(SR.net_perm_invalid_val, accessStr + "port", tmpStr));
                    }


                    listToAdd.Add(new EndpointPermission(host, port , transport));
                }
                else {
                    // improper tag found, just ignore
                }
            }
        }