CODEWITHSUNDEEP
c#.netlinq-to-xml
Andy May
Andy May

Reputation: 4070

Linq to XML - Check for null element while parsing for DateTime

Let's say I have the following XML:

<Account>
        <AccountExpirationDate>6/1/2009</AccountExpirationDate>
</Account>

I want to use LINQ to XML to parse this into an object I'll call Account:

public class Account {
    public DateTime? AccountExpirationDate { get; set; }
}

This is the C# code I've tried, but it won't let me use null:

var accountSettings = 
  from settings in templateXML.Descendants("Account")
  select new Account {
      AccountExpirationDate =   
         string.IsNullOrEmpty(settings.Element("AccountExpirationDate").Value) 
         ? DateTime.Parse(settings.Element("AccountExpirationDate").Value) 
         : null
  };

Is there a way for me to only assign AccountExpiration a date if the element exists in the XML? In my business logic it is acceptable for the value to be null. Thanks!

Upvotes: 2

Views: 5904

Answers (4)

guppy81
guppy81

Reputation: 91

For a more readable syntax and if you need such a check multiple times, you could use extension methods:

public static DateTime? ToDateTime(this Element e)
    {
        if (e == null)
            return null;

        if (string.IsNullOrEmpty(e.Value))
            return null;
        else
            return DateTime.Parse(e.Value);
    }

Upvotes: 0

Marc Gravell
Marc Gravell

Reputation: 1063383

You can just use:

from settings in templateXML.Descendants("Account")
let el = settings.Element("AccountExpirationDate")
let el2 = (el == null || string.IsNullOrEmpty(el.Value)) ? null : el
select new Account {
    AccountExpirationDate = (DateTime?)el2
};

there is a conversion operator that works this magic using standard xml datetime formatting, and which returns null if the element doesn't exist (note I don't read .Value).

Upvotes: 1

Mehrdad Afshari
Mehrdad Afshari

Reputation: 422112

var accountSettings =
  from settings in templateXML.Descendants("Account")
  select new Account {
    AccountExpirationDate = 
      string.IsNullOrEmpty((string)settings.Element("AccountExpirationDate")) 
            ? (DateTime?)null
            : DateTime.Parse(settings.Element("AccountExpirationDate").Value) 
  };

Upvotes: 2

Alexander Kahoun
Alexander Kahoun

Reputation: 2488

Try:

var accountSettings = from settings in templateXML.Descendants("Account")
                  where settings.Element("AccountExpriationDate") != null
                  && !String.IsNullOrEmpty(settings.Element("AccountExpriationDate").Value)
                  select new Account 
                  {
                      AccountExpirationDate = DateTime.Parse(settings.Element("AccountExpirationDate").Value)
                  };

Upvotes: 0

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