Handling null reference exception in linq

Question

Consider the following

var x= doc.Descendants("a").Where(p => p.Attributes["itemprop"].Value.Contains("image")).FirstOrDefault().Attributes["href"].Value;

Descendants might return null

Where might return null

Value might return null

Attributes might Be null etc..

is a try catch my only option to set the variable to null with the linq syntax to avoid the null reference exception, i simply want to set the variable to null and i don't want to split it out and use multiple if statements to check?

try
{
  x= doc.Descendants("a").Where(p => p.Attributes["itemprop"].Value.Contains("image")).FirstOrDefault().Attributes["href"].Value;
}
catch
{
  x=null;
}

http://stackoverflow.com/q/5753430/11683 and http://stackoverflow.com/q/4660142/11683 — GSerg, Mar 30 '14 at 17:04

score 2 · Accepted Answer · answered Mar 30 '14 at 17:11

Descendants can't return null it always return IEnumerable<T>

Where can't return null it return IEnumerable<T>

Attributes might Be null yes but you can avoid using Value you can use (string)p.Attributes["itemprop"] instead of p.Attributes["itemprop"].Value

so you can write your query as:

string val;

var x= doc.Descendants("a")
           .Where(p => (((string)p.Attributes["itemprop"]) ?? string.Empty)
                              .Contains("image"))
           .FirstOrDefault();
if(x != null)
{
    val = (string)Attributes["href"];
}

Handling null reference exception in linq

1 Answers1