refer : http://xml-rpc.net/, add reference CookComputing.XmlRpcV2.dll file on your project in c#,

        using CookComputing.XmlRpc;

        [XmlRpcUrl("http://localhost:8069/xmlrpc/common")]

        public interface IOpenErpLogin : IXmlRpcProxy

        {

            [XmlRpcMethod("login")]

            int login(string dbName, string dbUser, string dbPwd);

        }

        private void button1_Click(object sender, EventArgs e)

        {

          

            //Login to openerp

            IOpenErpLogin rpcClientLogin = XmlRpcProxyGen.Create<IOpenErpLogin>(); //add  XmlRpcProxyGen.CS File from src folder if required,

            int userid = rpcClientLogin.login(dbname, userName, pwd);

            MessageBox.Show(userid.ToString());

        }

For reference. My problem was solved reading another post here.. that when creating an instance of a hosted Odoo on Odoo.com, you need to go and change the password of the user, before it actually can be "seen".

Doing that had my code working like a charm.

Hi,

we create a mapper for xml-rpc to REST written in C#

https://odoorestapi.azurewebsites.net/Help