Question

If I do something like:

DataSet ds = GetMyDataset();

try
{
    string somevalue = ds.Tables[0].Rows[0]["col1"];
}
catch
{
    //maybe something was null
}

Is there a good way to check for null values without using the try/catch? It’s just that I don’t care if the value in “col1” is null, OR if “col1” didn’t exist, OR if there were no rows returned, OR if the table doesn’t exist!

Maybe I should care? 🙂
Maybe try/catch is the best way of approaching this but I just wondered if there was another way to do it?

Thanks!

Answer 1

I think May be Monad is best thing for this situation (Sample is from source):

public static TResult With<TInput, TResult>(this TInput o, 
       Func<TInput, TResult> evaluator)
       where TResult : class where TInput : class
{
  if (o == null) return null;
  return evaluator(o);
}

string postCode = this.With(x => person)
                      .With(x => x.Address)
                      .With(x => x.PostCode)

for your case is similar to:

ds.With(x=>Tables[0]).With(x=>x.Rows).With(x=>x[0])...

you will create an extension class and use it without worring about null references, Also Return method is useful for you see link.