Static method doesn't return value

Question

What am I doing wrong? Once the execution goes outside VKRequest.Dispatch, tmp looses data and returns null.

Update

public class GroupClass
{
    private static LinkedList<GroupClass> tmp = new LinkedList<GroupClass>();
    /* some code */
    public static LinkedList<GroupClass> GetGroupList()
    {
        VKRequest.Dispatch<VKList<VKGroup>> ( new VKRequestParameters ( "groups.get", "extended", "1", "filter", "admin, editor, moder", "fields", "photo_100" ), ( res ) =>
        {
            if ( res.ResultCode == VKResultCode.Succeeded && res.Data.count > 0 )
            {
                var item = res.Data.items[0];
                tmp.AddLast( new GroupClass ( item.id, item.name, item.screen_name, item.photo_100 ) );                            
            }
        }); //here
        return tmp;
    }
}

tmp should be initialized either inside the method or outside as static member. Can you please update your code? — Umesh, May 23 '16 at 10:20

score 0 · Answer 1 · edited May 23 '17 at 11:59

you should copy your variable into local variable before calling a lambda expression. you can find more explaination here.

public class GroupClass
{
    private static LinkedList<GroupClass> tmp = new LinkedList<GroupClass>();
    /* some code */
    public static LinkedList<GroupClass> GetGroupList()
    {
        var tmp1 = tmp;
        VKRequest.Dispatch<VKList<VKGroup>> ( new VKRequestParameters ( "groups.get", "extended", "1", "filter", "admin, editor, moder", "fields", "photo_100" ), ( res ) =>
        {
            if ( res.ResultCode == VKResultCode.Succeeded && res.Data.count > 0 )
            {
                var item = res.Data.items[0];
                tmp1.AddLast( new GroupClass ( item.id, item.name, item.screen_name, item.photo_100 ) );                            
            }
        }); //here
        return tmp1;
    }
}

Thanks for helping, but still `null` – John Slow May 23 '16 at 14:28 — John Slow, May 23 '16 at 14:28

Static method doesn't return value

1 Answers1