I cant add any item to the list I cant add list to list NullReferenceException RSS

• • Reply
  

  Mstkk

  Member

  9 Points

  42 Posts

  I cant add any item to the list I cant add list to list NullReferenceException

  Feb 24, 2013 09:28 PM|LINK

  Here my Product Class

    public class Product
      {
          public int ID { get; set; }
          public string Name { get; set; }        
          public virtual List<ProductPicture> Picture { get; set; }
          public virtual List<Supplier> Supplier { get; set; }
      }

  Here my Picture Repository

   public List<ProductPicture> GetProductPhotos(string pid)
          {
              sp = new SqlProvider();
              List<ProductPicture> piclist = new List<ProductPicture>();
              sp.AddParamatersString("@pid", pid);
              DataTable dt = sp.ExecuteMethod("select * from Products as p join ProductPictures as pic on p.ID=pic.Product_ID where p.ID=@pid");
              foreach (DataRow item in dt.Rows)
              {
                  ProductPicture pic = new ProductPicture();
                  pic.ID = (int)item["ID"];
                  pic.ProductID= Convert.ToInt16(pid);
                  pic.Path = item["Path"].ToString();
                  pic.IsDefault =Convert.ToBoolean( item["IsDefault"]);
                  piclist.Add(pic);
              }
              return piclist.ToList<ProductPicture>();
          }

  Here Product Repository 
   

   public IList<Product> GetAllProduct()
          {
              sp = new SqlProvider();
              ProductPictureRepository pPictureRepository = new ProductPictureRepository();
              List<ProductPicture> piclist = new List<ProductPicture>();
              CategoryRepository catRepository = new CategoryRepository();
              List<Product> plist = new List<Product>();
              DataTable dt = sp.ExecuteMethod("select * from Products");
              foreach (DataRow item in dt.Rows)
              {
                  Product p = new Product();
                  p.ID = (int)item["ID"];
                  piclist.AddRange((List<ProductPicture>)pPictureRepository.GetProductPhotos(p.ID.ToString()));
                  p.Brandid = (int)item["Brand_ID"];
                  p.Category = catRepository.GetCategorywithPid(p.ID.ToString()) as Category;
                  p.IsNew = Convert.ToBoolean(item["IsNew"]);
                  p.IsRecommended = Convert.ToBoolean(item["IsRecommended"]);
                  p.IsSpecial = Convert.ToBoolean(item["IsSpecial"]);
                  p.Name = item["Name"].ToString();
                  p.Picture.AddRange(piclist);
                  
                  p.OnOrder = Convert.ToInt32(item["OnOrder"]);
                  p.CreatedDate = Convert.ToDateTime(item["CreatedDate"]);
                  plist.Add(p);
              }
              return plist;
  
          }

  I am Getting error in the underlined Line "NullReferenceException was unhandled by user code"

  I cant Add any item on P.Picture i try every way But i cant add any item on this p.picture 

• • Reply
  

  Mstkk

  Member

  9 Points

  42 Posts

  Re: I cant add any item to the list I cant add list to list NullReferenceException

  Feb 24, 2013 09:34 PM|LINK

  That lines work good But

  List<ProductPicture> piclist = new List<ProductPicture>();
  
  piclist.AddRange((List<ProductPicture>)pPictureRepository.GetProductPhotos(p.ID.ToString()));
  

  That Lines Doesnt Work !

   p.Picture.AddRange((List<ProductPicture>)pPictureRepository.GetProductPhotos(p.ID.ToString()));

  This Line Doesnt Work They are same codes ! just different p.picture on my Product class like this 

     public virtual List<ProductPicture> Picture { get; set; }

  
  
  

  • Edited by Mstkk on Feb 24, 2013 09:35 PM
• • Reply
  

  markfitzme

  All-Star

  15367 Points

  2365 Posts

  Re: I cant add any item to the list I cant add list to list NullReferenceException

  Feb 24, 2013 11:27 PM|LINK

  In the constructor for the product do you initialize the list? If not, try Picture = new List<ProductPicture>() in the constructor.

  Usually this error comes about when you are trying to work with a property or variable that isn't initialized yet. In other words, p.Picture is a null reference exception because p.Picture hasn't been initialized with a new list.

  Not guaranteed that this is it, but it's worth a shot.

  Don't forget to mark useful responses as Answer if they helped you towards a solution.
• • Reply
  

  Mstkk

  Member

  9 Points

  42 Posts

  Re: I cant add any item to the list I cant add list to list NullReferenceException

  Feb 25, 2013 01:27 PM|LINK

  markfitzme

  In the constructor for the product do you initialize the list? If not, try Picture = new List<ProductPicture>() in the constructor.

  Usually this error comes about when you are trying to work with a property or variable that isn't initialized yet. In other words, p.Picture is a null reference exception because p.Picture hasn't been initialized with a new list.

  Not guaranteed that this is it, but it's worth a shot.

  p.Picture = piclist.ToList();

  
  
  

   i  equalize that 2 list (no to add ) and this work .. For now..

  • Marked as answer by Mstkk on Feb 25, 2013 01:27 PM