Maintain Session While Calling an ASMX Web Service

Question

I am using a client app to connect to a web service for authenticated user only. Here is simplest example:
My web service code:

public class TestService : System.Web.Services.WebService
{
    [WebMethod(EnableSession = true)]
    public string WelcomeMsg()
    {
        return "Hello: " + Session["UserName"] + "! Welcome to our store.";
    }

    [WebMethod(EnableSession = true)]
    public void SetUserName(string sName)
    {
        Session["UserName"] = sName;
    }
}

Here is my code on client app (Windows form, not web base):

private void btnSetName_Click(object sender, EventArgs e)
{
    TestService.TestService ws = new TestService.TestService(); //Create a web service
    MainForm.m_ccSessionInfo = new System.Net.CookieContainer(); //Create a CookieContainer
    ws.CookieContainer = MainForm.m_ccSessionInfo; //Set CookieContainer of the web service
    ws.SetUserName(txtUserName.Text); //Set value of session 
    ws = null;
}

private void btnWelcome_Click(object sender, EventArgs e)
{
    TestService.TestService ws = new TestService.TestService(); //Create a web service
    ws.CookieContainer = MainForm.m_ccSessionInfo; //Set CookieContainer back
    string sWelcome = ws.WelcomeMsg(); //Get value from session property
    ws = null;

    System.Diagnostics.Debug.WriteLine(sWelcome); 
}

In my example MainForm.m_ccSessionInfo is a static member, I want to keep the session cookies value in this one!
However, it don't work :( . The ws.WelcomeMsg() is always return an empty string.

Answer 1

Oops, I think I've just found the solution for this problem. The CookieContainer is created by server and must be kept at client app. On btnSetName_Click, I change

MainForm.m_ccSessionInfo = new System.Net.CookieContainer(); //Create a CookieContainer
ws.CookieContainer = MainForm.m_ccSessionInfo; //Set CookieContainer of the web service

into

ws.CookieContainer = new System.Net.CookieContainer(); //Create a CookieContainer
MainForm.m_ccSessionInfo = ws.CookieContainer; //Keep CookieContainer for later using

And it works well now! Thanks you all.