ช่วยผมแปลง Enumeration ใน java เป็น code C# ผมอ่านแล้วไม่เข้าใจ

Hashtable<String,String> categoryTable;
 public FormatArff() throws Exception {
    categoryTable=new Hashtable<String,String>();
  }
fw.write("@attribute " + keywordTable.size() + " {");
    Enumeration<String> enumerate=categoryTable.keys();
    Boolean isFirst=true;
    while(enumerate.hasMoreElements()) {
      if(isFirst) {
        fw.write((String)enumerate.nextElement());
        isFirst=false;
      }
      else
        fw.write("," + (String)enumerate.nextElement());
    }

StreamWriter sw = new StreamWriter(HttpContext.Current.Server.MapPath("Model/test.arff"));
//Looking through all Items of a Hashtable
        IEnumerator enumerate = categoryTable.Keys;
        bool isFirst = true;
        while (enumerate.MoveNext())
        {
            if (isFirst)
            {
                sw.WriteLine(enumerate.MoveNext());
                isFirst = false;
            }
            else
                sw.WriteLine("," + enumerate.MoveNext());
        }