selenium - Login Programmatically to DotNetNuke -

i'm working on windows console application base on c#. in app user enter username , password (assume gmail.com) should let them access other part of program if logged in successfully, if not won't permission.
search around these topics:
- post , get
- webrequest
- selenium

first checked msdn sample code received page source code! check selenium , should worked fine somehow. here code:

using system; using system.collections.generic; using system.linq; using system.text; using system.threading.tasks;  using openqa.selenium; using openqa.selenium.firefox; using openqa.selenium.support.ui;  namespace gmail_login {     class program     {         static void main(string[] args)         {             iwebdriver driver = new firefoxdriver();             driver.navigate().gotourl("http://gmail.com/");              //find target fields             iwebelement user = driver.findelement(by.name("email"));             iwebelement pass = driver.findelement(by.name("passwd"));             iwebelement submit = driver.findelement(by.name("signin"));             //[end]                user.sendkeys("urusernamexd");             pass.sendkeys("urpass^_^");              // submit login form             submit = driver.findelement(by.name("signin"));             submit.click();             //[end]              //result             string url = driver.url;              //check stat             if (url == "https://mail.google.com/mail/?shva=1")             {                 console.writeline("login successfully");                 driver.close();              }         }     } } 

this worked fine open real browser. want check these information without opening browser, possible?!!!
solve checked web-kit , i'm totally confused.
question is:
how can send user login information server, submit form if needed , response (not page source code!) ?
thanks.

note: site i'm working on base on "dotnetnuke cms"