xml條件XElement創建

Question

我建立這個xml檔案：

   var persons = new[] {
   new Person {
      Name = "Patrick Hines",
      PhoneNumbers = new[] { "206-555-0144", "425-555-0145" }
   },
   new Person {
      Name = "Gretchen Rivas",
      PhoneNumbers = new[] { "206-555-0163" }
   }
};
            XElement contacts =
               new XElement("contacts",
                  from p in persons
                  where p.Name.StartsWith("G")
                  select new XElement("contact",
                     new XElement("name", p.Name),
                     from ph in p.PhoneNumbers
                     select new XElement("phone", ph)
                  )
               );


        class Person
        {
            public string Name;
            public string[] PhoneNumbers;
        }

在此示例中，電話號碼不為null。 當電話號碼字符串為空或null時，如何在XML中不會創建元素的方式編碼？

Answer 1

從電話號碼中過濾出空字符串：

   from ph in p.PhoneNumbers where !String.IsNullOrEmpty(ph)