WCF getting entity from WCF service

Question

I have a WCF Service Library and Widnows Form as a client. I have database ADO.NET EF I want to list all of the products (clothes) with their sizes. (Relation 1 to many).

public partial class ProductsEntity
{
    public ProductsEntity()
    {
        this.Sizes = new HashSet<SizesEntity>();
    }

    public int ID { get; set; }
    public string Name { get; set; }
    public decimal Price { get; set; }

    public virtual ICollection<SizesEntity> Sizes{ get; set; }
}

this is my data contract:

[DataContract]
public class Products
{
    [DataMember]
    public int ID { get; set; }
    [DataMember]
    public string Name{ get; set; }
    [DataMember]
    public decimal Price { get; set; }
    [DataMember]
    public virtual ICollection<SizesEntity> Sizes{ get; set; }

}

 [DataContract]
public class Sizes
{

    [DataMember]
    public int ID { get; set; }
    [DataMember]
    public int Name { get; set; }
    [DataMember]
    public Nullable<int> Quantity { get; set; }
    [DataMember]
    public int ID_Product { get; set; }

    [DataMember]
    public virtual ProductsEntity Products { get; set; }

}

i dont have this in data base, but i added Products_with_sizes for my query (Im not sure its a good way of dealing with it)

[DataContract]
public class Products_with_sizes
{
    [DataMember]
    public int ID { get; set; }
    [DataMember]
    public string Name { get; set; }
    [DataMember]
    public decimal Price { get; set; }
    [DataMember]
    public int S { get; set; }
    [DataMember]
    public int M { get; set; }
    [DataMember]
    public int L { get; set; }
}

using (var context = new dbMagazynierEntities())
            {
                var q = (from p in context.Products
                            where p.Name.Contains(name) && p.Price>= Price_from && p.Price <= Price_to
                            join r in context.Sizes
                                on p.ID equals r.Prodcuts.ID
                                into sizes
                            select new
                            {
                                ID = p.ID,
                                Name= p.Name,
                                Price = p.Price,
                                S = sizes.Where(x => x.Name== 0).Sum(x => x.Quantity) ?? 0,
                                M = sizes.Where(x => x.Name== 1).Sum(x => x.Quantity) ?? 0,
                                L = sizes.Where(x => x.Name== 2).Sum(x => x.Quantity) ?? 0,
                            });
                odp = new List<Products_with_sizes>();
                foreach (var item in q)
                {
                    odp.Add(new Products_with_sizes{ ID = item.ID, Name= item.Name, Price = item.Price, S = item.S, M = item.M, L = item.L });
                }

so know I use this method in my client and i get error

                         wyn = context.SzukajProduktu(id, name.Text, price_from, price_to);

i get:

Cannot implicitly convert type 'System.Collections.Generic.List<Magazynier2WindowsFormsApplication.ServiceReference1.MyServiceProducts_with_sizes>' to 'System.Collections.Generic.List<Magazynier2ServiceLibrary.MyService.Products_with_sizes>'   

Answer 1

I resolved it by changing

    [OperationContract]
    List<WCFLIB.MyService.Products_with_sizes> SzukajProduktu(int id, string name, decimal price_form, decimal price_to);

to

[OperationContract]
    List<MyService.Products_with_sizes> SzukajProduktu(int id, string name, decimal price_form, decimal price_to);

Answer 2

public List<Prodcuts_with_sizes> SzukajProduktu(int id, string name, decimal price_from, decimal price_to)
    {
        List<Prodcuts_with_sizes> odp;
        if (id == -1) //when id is not given
        {
            using (var context = new dbMagazynierEntities())
            {
                var q = (from p in context.Products
                            where p.Name.Contains(name) && p.Price >= price_from && p.Price <= price_to
                            join r in context.Size
                                on p.ID equals r.Products.ID
                                into sizes
                            select new
                            {
                                ID = p.ID,
                                Name = p.Name,
                                Price = p.Price,
                                S = sizes.Where(x => x.Name == 0).Sum(x => x.Quantity) ?? 0,
                                M = sizes.Where(x => x.Name == 1).Sum(x => x.Quantity) ?? 0,
                                L = sizes.Where(x => x.Name == 2).Sum(x => x.Quantity) ?? 0,
                            });
                odp = new List<Prodcuts_with_sizes>();
                foreach (var item in q)
                {
                    odp.Add(new Prodcuts_with_sizes { ID = item.ID, Name = item.Name, Price = item.Price, S = item.S, M = item.M, L = item.L });
                }
                //dataGridView1.DataSource = q.ToList();
            }
            return odp;
        }
        else //when id is given
        {
            using (var context = new dbMagazynierEntities())
            {
                var q = (from p in context.Products
                            where p.ID == id
                            join r in context.Sizes
                                on p.ID equals r.Products.ID
                                into sizes
                            select new
                            {
                                ID = p.ID,
                                Name = p.Name,
                                Price = p.Price,
                                S = sizes.Where(x => x.Name == 0).Sum(x => x.Quantity) ?? 0,
                                M = sizes.Where(x => x.Name == 1).Sum(x => x.Quantity) ?? 0,
                                L = sizes.Where(x => x.Name == 2).Sum(x => x.Quantity) ?? 0,
                            });
                odp = new List<Prodcuts_with_sizes>();
                foreach (var item in q)
                {
                    odp.Add(new Prodcuts_with_sizes { ID = item.ID, Name = item.Name, Price = item.Price, S = item.S, M = item.M, L = item.L });
                }
            }
            return odp;

        }
    }


 using (var context = new MyInterfaceClient())
                {
                     wyn = context.SzukajProduktu(id, name.Text, price_from, price_to);
                    //return wyn;
                }

Answer 3

By looking at your exception, it seems that you're trying to directly cast a class generated by your service proxy to the DTO you created yourself.

Even though those 2 classes have the same name and properties, they are in fact different (i.e. have no common parent or inteface) and are in a different namespace.

You should write a method that would translate the proxy generated class to your DTO class explicitely, e.g.

List<Magazynier2ServiceLibrary.MyService.Products_with_sizes> TranslateProxyClassToDTO(List<Magazynier2WindowsFormsApplication.ServiceReference1.MyServiceProducts_with_sizes> input)
{
    // translate all items and their properties and return the translated list
}