ASMX ASP.NET，按服务方法返回的怪异类型

Question

I'm new in ASP.NET. I wanted to create a simple Web Service containing of one method:

Here's the code:

    [WebService(Namespace = "http://cstest.pl/PaintService.asmx/")]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [System.ComponentModel.ToolboxItem(false)]
    public class PaintService : WebService
    {
        private Random r = new Random();  

        [WebMethod(Description =("Something"))]
        public Nullable<Point> StartDraw(int startX, int startY, int width, int height)
        {
            try
            {
                int X = r.Next(startX, width);
                int Y = r.Next(startY + height);
                return (new Point(X, Y));
            }
            catch (ArgumentOutOfRangeException e)
            {
                Console.WriteLine(e.Message);
                return null;
            }
        }
    }

Then I've got a client class that gives me an error "Cannot implicitly convert type 'WinFormsConsumer.localhost.Point' to 'System.Drawing.Point" .

localhost is the name of the web service which I've added to WinFormsConsumer class as Add Service Refference... , by choosing Web Refference and passing http://localhost:2540/PaintService.asmx?wsdl .

using System;
using System.Collections;
using System.Drawing;
using System.Windows.Forms;

    namespace WinFormsConsumer  
     {
            public partial class Form1 : Form
            {
                localhost.PaintService ps = new localhost.PaintService();

                private Random r = new Random();
                private Timer timer = new Timer();
                private ArrayList list = new ArrayList();

               public Form1()
               {
                  ...
               }

                private void Timer_Tick(object sender, EventArgs e)
                {
                   //below line gives the error
                   Point temp = ps.StartDraw(ClientRectangle.X, 
        ClientRectangle.Y, ClientRectangle.Width, ClientRectangle.Height);
                    this.Invalidate();
                }
            }
      }

Why do I get this error? I don't understand it, why it seems like the type of Point returned from Web Service is "different" that those defined in System? What am I missing?

Answer 1

Visual Studio will not reuse all types exposed by web services by default. It is treating System.Drawing.Point as a third-party type and defining a "proxy" that matches it's signature. You have to tell it which types you want to "reuse" in the proxy.

Edit the service reference and check the box that says "Reuse types in specified referenced assemblies." Then make sure "System.Drawing.DLL" is available and selected

More info on MSDN .

Answer 2

I've made some research and the answer is: it's impossible. This is the weak side of ASMX and one of reasons why the WCF was introduced. I've found some work arounds, like creating 'SwallowCopy' class etc., but it's not really good thing to do and works with classes only.

So assuming what I've said, plus it's just a project and I have to use it, I've decided to just use the proxy object. The client doesn't have to know about it and it fits my needs right now.