Convert FQL Results to custom class?

问题

I am a fairly new C# programmer and am getting stuck on trying to convert FQL results into a custom class...for example, I am doing the following, but it seems like a lot of steps...I was just returning a datatable, but wanted the result to be strongly typed class collection. I'd appreciate any insights. I'm open to other ways of achieving similar results as well.

Thanks, Chad

public class FacebookFriends
{
    public string FriendID { get; set; }
    public string FriendName { get; set; }
    public string PicURLSquare { get; set; }
    public string ProfileLink { get; set; }

    //Gets your FB friends that are NOT currently using this application so you can invite them
    public IEnumerable<FacebookFriends> GetFriendsNotUsingApp()
    {
        string strQuery = "SELECT uid, name, pic_square, link FROM user WHERE uid IN (SELECT uid2 FROM friend WHERE uid1=me()) AND NOT is_app_user";

        FacebookSDKInterface objFQL = new FacebookSDKInterface();
        dynamic objFNU = objFQL.FBFQL(strQuery);

        //Construct the new, formated, merged datatable to store the results the way we want them   
        DataTable dtFriendsNotUsingApp = new DataTable();    
        dtFriendsNotUsingApp.Columns.Add("FriendID");
        dtFriendsNotUsingApp.Columns.Add("FriendName");
        dtFriendsNotUsingApp.Columns.Add("PicURLSquare");
        dtFriendsNotUsingApp.Columns.Add("Link");

        if (objFQL != null)
        {
            foreach (dynamic row in objFNU.data)
            {
                //Add New DataRow to new DataTable
                DataRow drRow = dtFriendsNotUsingApp.NewRow();

                //Get various values from original JSON Friend List returned
                drRow["FriendID"] = row.uid;
                drRow["FriendName"] = row.name;
                drRow["PicURLSquare"] = row.pic_square;
                drRow["Link"] = row.link;

                //Add New Row to New Resulting Data Table
                dtFriendsNotUsingApp.Rows.Add(drRow);
            }

            dtFriendsNotUsingApp.DefaultView.Sort = "FriendName";
        }

        IEnumerable<FacebookFriends> objFriendsListCollection = null;

        var toLinq = from list in dtFriendsNotUsingApp.AsEnumerable()
                     select new FacebookFriends
                     {
                         FriendID = list["FriendID"].ToString(),
                         FriendName = list["FriendName"].ToString(),
                         PicURLSquare = list["PicURLSquare"].ToString(),
                         ProfileLink = list["ProfileLink"].ToString()
                     };

        objFriendsListCollection = toLinq.OrderByDescending(p => p.FriendName);

        return objFriendsListCollection;

    } //Get FB Friends not already using this app

回答1:

I belive this may help.

1st: I've never used the Facebook API, so I'm just using your code as an example.

2nd: As the method is inside the class, I've changed it to static. This way, you can use it by simply calling FacebookFriends.GetFriendsNotUsingApp(), instead of new FacebookFriends().GetFriendsNotUsingApp().

3rd The code:

    public class FacebookFriends
    {
        public string FriendID { get; set; }
        public string FriendName { get; set; }
        public string PicURLSquare { get; set; }
        public string ProfileLink { get; set; }

        //Gets your FB friends that are NOT currently using this application so you can invite them
        public static IEnumerable<FacebookFriends> GetFriendsNotUsingApp()
        {
            string strQuery = "SELECT uid, name, pic_square, link FROM user WHERE uid IN (SELECT uid2 FROM friend WHERE uid1=me()) AND NOT is_app_user";

            FacebookSDKInterface objFQL = new FacebookSDKInterface();
            dynamic objFNU = objFQL.FBFQL(strQuery);

            List<FacebookFriends> friendsToReturn = new List<FacebookFriends>();

            if (objFQL != null)
            {
                foreach (dynamic row in objFNU.data)
                {
                    friendsToReturn.Add(new FacebookFriends()
                        {
                            FriendID = row.uid,
                            FriendName = row.name,
                            PicURLSquare = row.pic_square,
                            ProfileLink = row.link
                        }
                    );
                }
            }

            return friendsToReturn;
        } //Get FB Friends not already using this app
    }

Hope this helps.

Regards

回答2:

I have no experience with Facebook API or FQL as well, but by looking at your code objFNU.data appears to implement IEnumerable, hence you can use LINQ extension methods directly with it:

public class FacebookFriends
{
    public string FriendID { get; set; }
    public string FriendName { get; set; }
    public string PicURLSquare { get; set; }
    public string ProfileLink { get; set; }

    //Gets your FB friends that are NOT currently using this application so you can invite them
    public static IEnumerable<FacebookFriends> GetFriendsNotUsingApp()
    {
        string strQuery = "SELECT uid, name, pic_square, link FROM user WHERE uid IN (SELECT uid2 FROM friend WHERE uid1=me()) AND NOT is_app_user";

        FacebookSDKInterface objFQL = new FacebookSDKInterface();
        dynamic objFNU = objFQL.FBFQL(strQuery);

        if (objFQL != null) // shouldn't you check objFNU for being null here instead?
        {
            IEnumerable<dynamic> objFNUdata = (IEnumerable<dynamic>)objFNU.data; // explicit cast might not be necessary
            return objFNUdata.Select(row => new FacebookFriends()
                {
                    FriendID = row.uid,
                    FriendName = row.name,
                    PicURLSquare = row.pic_square,
                    ProfileLink = row.link
                }).OrderByDescending(p => p.FriendName);
        }
        else
        {
            return new List<FacebookFriends>();
        }
    } //Get FB Friends not already using this app
}

回答3:

In the end, this worked best for me. Thanks to both, and especially @DarmirArh for all his help in getting this to work.

try
        {
            FacebookSDKInterface objFQL = new FacebookSDKInterface();
            dynamic objFNU = objFQL.FBFQL(strQuery);

            if (objFNU != null) // shouldn't you check objFNU for being null here instead?
            {
               IEnumerable<dynamic> objFNUdata = (IEnumerable<dynamic>)objFNU.data; // explicit cast might not be necessary
               IEnumerable<FacebookFriends> objMyFriends =
               from row in objFNUdata
               select new FacebookFriends()
               {
                   FriendID = row.uid,
                   FriendName = row.name,
                   PicURLSquare = row.pic_square,
                   ProfileLink = row.profile_url
               };

               objMyFriends = objMyFriends.OrderBy(p => p.FriendName);
               return objMyFriends;
            }
            else
            {
                return new List<FacebookFriends>();
            }
        }
        catch (Exception ex)
        {
            return new List<FacebookFriends>();
        }

来源：https://stackoverflow.com/questions/11623714/convert-fql-results-to-custom-class