Question

Hi
I want to read an XML document but it may have some of the node missing and if so I want to use a defualt value for the missing nodes.

XDocument xmlDoc = XDocument.Load(Path.Combine(Application.StartupPath, "queues.xml"));
        var q = from c in xmlDoc.Root.Descendants("Queue")
                select new Queue
                {
                    Alert1 =c.Element("Alert1").Value,
                    Alert2 = c.Element("Alert2").Value,
                    Alert3 =c.Element("Alert3").Value
                };

        var queryAsList = new BindingList<Queue>(q.ToList());


    class Queue
{
    public string Alert1 { get; set; }
    public string Alert2 { get; set; }
    public string Alert3 { get; set; }
}

so in the above only alert1 may exist or all the alerts or none of the alerts! I need to use a default Value for any nodes that does not exist!

I thought I could Alert3 =c.Element(“Alert3”).Value.DefaultEmpty(“abc”) but this doesn’t work!

Answer 1

XDocument xmlDoc = XDocument.Load(Path.Combine(Application.StartupPath, "queues.xml"));
var q = from c in xmlDoc.Root.Descendants("Queue")
        select new Queue
        {
            Alert1 = (string)c.Element("Alert1") ?? "default 1",
            Alert2 = (string)c.Element("Alert2") ?? "default 2",
            Alert3 = (string)c.Element("Alert3") ?? "default 3"
        };

And it is fixed. This also works for things like (int?), (DateTime?) via a range of conversion operators defined on the nodes, so it is easier to write and safer re missing data.