Hi,

I want to use XPO inside a web method of a web service. I think I have to create the DataLayer inside the web method because the web method is stateless. Is this correct? Also, do I have to be careful how I create the DataLayer or is it the same as in a WinForm application?

 
Thanks,

Petros
 

This is some dirty hack code we using internally:

    [WebMethod]
    public void SubmitMonitorMessage(AgentMessageType messageType, string client, string service, string message, string info) {
        session = new UnitOfWork();
        session.ConnectionString = ConfigurationManager.ConnectionStrings["ConnectionStringForDevelopment"].ConnectionString;

        AgentMessage msg = new AgentMessage(session);
        msg.MessageType = messageType;
        msg.Client = client;
        msg.Service = service;
        msg.When = DateTime.Now;
        msg.ExpiresOn = msg.When.AddMinutes(AgentMessage.MonitorIntervalMin);
        msg.Message = message;
        msg.Info = info;
        session.CommitChanges();
    }

This example assumes that XAF security is not used and web service is in separate web application. If you add your webservice as a part of XAF application and want to use its security features, code would be different.

I am sorry I marked this post as answered and now I mark it unanswered again, but I just realized I was not looking exactly what article "How to use XPO with a Web Service" describes. Let me explain. I am not looking to use a web service as a gate that will enable me to directly connect a CF client using XPO. I want to call a regular web method from a CF client that returns a simple type. But inside that web method I want to connect to a local database using XPO. I have managed to do this, but it seems the way I am creating the DataLayer inside the web method causes problems after a while with pool connections. Now I know this might be an entirely "How to connect to the database inside a web service method" subject, but I would appreciate it if anyone with web services experience sheds some light.

My Web Service solution doesn't have a Global.asax file. The code for my simple web method is this:

[WebMethod]

public string GetDescription(int oid)

{
  string database = Settings.Default.Database;
  XpoDefault.DataLayer = XpoDefault.GetDataLayer(MSSqlConnectionProvider.GetConnectionString(database, "Scrapyard"),
  AutoCreateOption.SchemaAlreadyExists);

  using (Session session = new Session())

  {

    Car car = session.GetObjectByKey<Car>(oid);

    if (car != null)

    {

      return car.Description;
    }

    return string.Empty;
  }
}

This code means that each time the web method is called, a new datalayer is created as well as a connection? The problem is that after several calls, I get an exception that no more connections can be created because the pool is full. What should I do? I have tried adding a Global.asax file and create the DataLayer in the Application_Start event, but it stopped working completely and my web methods tried to create the default connection. Where should I create the connection and in what way to comply with web services logic?

Thank you
Petros

It turns out that I should close the connections made by XPO. Do you know how to explicitly close a connection using XPO?

Ok, here is the answer. I should create a Global.asax and enter the following code:

protected void Application_Start(object sender, EventArgs e)
{
  string database = Settings.Default.Database;
  string schema = Settings.Default.Schema;
  XpoDefault.DataLayer = XpoDefault.GetDataLayer(MSSqlConnectionProvider.GetConnectionString(database, schema),
    AutoCreateOption.SchemaAlreadyExists);
}

This only creates one connection, not several connections per web method call.