Object Reference Not set to instance of an object error while using FirstOrDefault

Question

When I use this below code, I get object reference error, this might be because there is no match for "spider". My question is, How to check for null value in these situations

int fooID = foos.FirstOrDefault(f => f.Bar == "spider").ID;

I'm using this same scenario for different conditions for fetching different Items from the list like

int fooID = foos.FirstOrDefault(f => f.Bar == "spider").ID; 
String fooDescription = foos.FirstOrDefault(f => f.Sides == "Cake").Description; 

Is there any other way to check for null values.

Answer 1

The same way as you normally would, assign a variable and check it.

var foo = foos.FirstOrDefault(f => f.Bar == "spider");

if (foo != null)
{
    int fooID = foo.ID;
}

Based upon your updated example, you would need to do this instead:

var fooForId = foos.FirstOrDefault(f => f.Bar == "spider");
var fooForDescription = foos.FirstOrDefault(f => f.Sides == "Cake");

int fooId = fooForId != null ? fooForId.Id : 0;
string fooDescription = fooForDescription != null ? fooForDescription.Description : null; // or string.Empty or whatever you would want to use if there is no matching description.