Question

I am using C#, Linq to Entities and .Net 4

I am using the following code to extract a list of data. The data may be a number but for some records it may be null or some other form of data. Is it possible with Linq to extract just the numbers in this filed or do I need to use additional steps?

var s = (from t in context.Cards where t.CardData != null select t.CardData).ToList();

The above will return a list of strings but I’d like a list of int. The CardData field may be null, a number or some text. In the DB it is a nullable nvarchar field.

Answer 1

The simplest way to do this will be to use TryParse on each element of your returned list. You’ve already eliminated the null elements so you know you have something:

var numberList = new List<int>();
foreach (var item in s)
{
    int result = 0;
    if (Int32.TryParse(item, result))
    {
        numberList.Add(result);
    }
}

This has the added benefit that you’ll understand what it does 18 months from now.