Submitting an InfoPath Form to SharePoint Form Library Using Code Behind.

I am trying to submit an InfoPath 2010 form using code behind (VSTA 2010). My Form only include 1 Text Box (TextValue) & one button that labeled as "Submit" that will trigger the form submission code.The form name as "SubmitByCode".

The Code is at the below.

using Microsoft.Office.InfoPath;
using System;
using System.Xml;
using System.Xml.XPath;
using Microsoft.SharePoint;
using System.Data;

namespace SubmitByCode
{
    public partial class FormCode
    {
        // Member variables are not supported in browser-enabled forms.
        // Instead, write and read these values from the FormState
        // dictionary using code such as the following:
        //
        // private object _memberVariable
        // {
        //     get
        //     {
        //         return FormState["_memberVariable"];
        //     }
        //     set
        //     {
        //         FormState["_memberVariable"] = value;
        //     }
        // }

        // NOTE: The following procedure is required by Microsoft InfoPath.
        // It can be modified using Microsoft InfoPath.
        public void InternalStartup()
        {
            ((ButtonEvent)EventManager.ControlEvents["Submit"]).Clicked += new ClickedEventHandler(Submit_Clicked);
        }

        public void Submit_Clicked(object sender, ClickedEventArgs e)
        {
            //create the navigator 
            XPathNavigator nav = MainDataSource.CreateNavigator();

            int nextID = GetMaxID() + 1;
            //set the form name
            string formName = "MyForm" + DateTime.Now.Year.ToString() + " - " + nextID.ToString();
            //set the field to the form name
            nav.SelectSingleNode("/my:myFields/my:TextValue", NamespaceManager).SetValue(formName);
            //reference the submit connection
            //DataConnection spConn = DataConnection["SharePoint Library Submit"];

DataConnection SPConnection = (DataConnection)this.DataConnections["SharePoint Library Submit"];

            //submit the form
            SPConnection.Execute();

        }

        public int GetMaxID()
        {
            SPContext ctx = SPContext.Current;
            using (SPSite site = new SPSite(ctx.Site.Url))
            {
                using (SPWeb web = site.OpenWeb())
                {
                    try
                    {
                        SPList oList = web.Lists["Order Attachments"];
                        SPQuery query = new SPQuery();

                        query.Query = "";
                        SPListItemCollection items = oList.GetItems(query);

                        DataTable dtMax = new DataTable();
                        dtMax = items.GetDataTable();

                        return (dtMax == null) ? 0 : Convert.ToInt32(dtMax.Compute("Max(ID)", string.Empty));
                    }
                    finally
                    {
                        if (site != null)
                            site.Dispose();
                    }

                }
            }

        }
    }
}

But when I try to submit the form I got an error as "'Microsoft.Office.InfoPath.DataConnection' is a 'type' but is used like a 'variable'" at the

DataConnection SPConnection = DataConnection("SharePoint Library Submit");

statement. I think my references are OK but I cannot understand what this message is saying. Please can someone try to solve this error.

Regards,

Chiranthaka