I have this code :
public struct SmartFilter
{
public int from, to;
public ArrayList collect = new ArrayList();
public long bit;
}
i get error :
cannot have instance field initializers in structs
i try different way to get over this error without success,
how to have a array list in struct / class?
There are multiple problems there:
ArrayListnone of these is helping you...
with a class the initializer would work fine
with a property you could do lazy init:
public ArrayList Collect {
get { return collect ?? (collect = new ArrayList()); }
}
I would refactor to:
public class SmartFilter
{
public int From {get;set;}
public int To {get;set;}
private List<SomeKnownType> collect = new List<SomeKnownType>();
public List<SomeKnownType> Collect { get { return collect; } }
public long Bit {get;set;}
}
ref, or accessing directly in an array - not a list or similar). I use them myself very occasionally. But the vast majority of mutable structs I see are used inappropriately, and almost always are the underlying cause of the bug that I've been summoned to investigate.Eh, I'll let the guys with bigger brains than me explain why, but you can't do that. :) However you could do this...
class NotAStruct
{
public int from, to;
public ArrayList collect = new ArrayList();
public long bit;
}
...or this...
struct Blah
{
ArrayList doh;
public void SomeMethod()
{
doh = new ArrayList();
}
}
But neither is a good idea, as pointed out by several other people.
You should make a class of it, I wouldn't keep an ArrayList in a struct since struct should be used for simple data. Regarding the error you have I think you just can remove the new ArrayList(); and it should work.
I wrote this and it works just fine:
public struct MyStruct
{
public int intVal;
public ArrayList listVal;
public bool boolVal;
}
However, I really thing you should use a class instead; that is, use this instead:
public class MyClass {
public int IntVal {get; set;}
public ArrayList ListVal {get; set;}
public bool BoolVal {get; set;}
}
