How to convert this JavaScript code to C#?

/ Constants (Type)
	var TYPE_EUI64 = 'EUI-64';
	var TYPE_RA28 = 'RA-28';
	var TYPE_ADVA48 = 'ADVA-48';
	var TYPE_RADIO_PAYLOAD = 'RadioPayload';
	var TYPE_UNDEFINED = 'Undefined';
	// Constants
	var REELYACTIVE_OUI36 = '001bc5094';
	/**
	* Identifier Class
	* Represents an identifier
	* @param {string} type Type of identifier.
	* @param {Object} value The value of the given identifier.
	* @constructor
	*/
	function Identifier(type, value) {
	var isValue = (value != null);
	// Constructor for EUI-64
	if((type == TYPE_EUI64) && isValue) {
	this.type = TYPE_EUI64;
	this.value = value;
	}
	// Constructor for RA-28
	else if((type == TYPE_RA28) && isValue) {
	this.type = TYPE_RA28;
	this.value = value.substr(value.length - 7, 7);
	}
	// Constructor for ADVA-48
	else if((type == TYPE_ADVA48) && isValue) {
	this.type = TYPE_ADVA48;
	this.value = value;
	}
	// Constructor for RadioPayload
	else if((type = TYPE_RADIO_PAYLOAD) && isValue) {
	this.type = TYPE_RADIO_PAYLOAD;
	this.value = value.payload;
	this.lengthBytes = value.payloadLengthBytes;
	}
	// Constructor for Undefined
	else {
	this.type = TYPE_UNDEFINED;
	}
	};
	/**
	* Convert this identifier to a new one of the given type, if possible.
	* @param {string} newType New identifier type.
	*/
	Identifier.prototype.toType = function(newType) {
	var isEUI64Target = (newType === TYPE_EUI64);
	var isRA28Source = (this.type === TYPE_RA28);
	if(isEUI64Target && isRA28Source) {
	return new Identifier(TYPE_EUI64, REELYACTIVE_OUI36 + this.value);
	}
	return null;
	}
	module.exports = Identifier;
	module.exports.EUI64 = TYPE_EUI64;
	module.exports.RA28 = TYPE_RA28;
	module.exports.ADVA48 = TYPE_ADVA48;
	module.exports.RADIO_PAYLOAD = TYPE_RADIO_PAYLOAD;