What about Boolean.TryParse()? That way you could do it without a nullable type (if that is an option). The following should work.


#region private fields

bool _isValid = false;


#endregion private fields

IsValid = Boolean.TryParse(reader["IsValid"], out _isValid);

Another option (probably not a best practice but would work):

public static List<Foo> RetrieveDataFromSql(Foo foo)
{
List<SqlParameter> parameters = Database.CreateParameters(foo);
return Database.GetTable<Foo>(parameters, "sproc").FindAll(delegate (Foo foo) { return foo.IsValid != null && foo.IsValid; });
}

This way you have a List<T> of only true objects (or true / false if you alter the predicate).

I use this approach if wanting to display data to certain account types. For example, a manager might want all the historical data returned while the employee should only view data from today outwards. That's been a requirement in the past and all I do is pass in a bool "isManager" or something similar.

List<T> list = Database.GetTable<T>(parameters, "sproc");
return isManager ? list : list.FindAll(delegate (T t) { return t.DateTimeField.Date >= DateTime.Today.Date; });

To get back on-topic, if I can help it I filter by NOT NULL in a view somewhere (or table by way of stored procedure). I usually don't even display this field as output, simply a WHERE clause.