keep session alive using webclient - webclient

Question

I'm trying to program an application connecting to a website not spammer but some thing like that .
But there is one problem :
In that website you will login by an html form and I know the target php page and parameters so with c# I login like this :
using (WebClient wc = new WebClient())
{
wc.Headers[HttpRequestHeader.ContentType] = "application/x-www-urlencoded";
wc.UploadString("http://example.com/login/check.php", "username=US&password=PW");
MessageBox.Show(result);
}
after logining in when I want to ( for example ) send a post ( like codes below ) the answer is that you are not loged in !
using (WebClient wc = new WebClient())
{
wc.Headers[HttpRequestHeader.ContentType] = "application/x-www-urlencoded";
wc.UploadString("http://example.com/post/send.php", "title=T&body=B");
MessageBox.Show(result);
}
I think the problem is that the session is closed .
what can I do ?

Answer 1

I dont know if you found the answer but try this
WebClient webClient = new WebClient();
string url = #"http://example.com/login/check.php";
var postData = new System.Collections.Specialized.NameValueCollection();
byte[] bytes = webClient.UploadValues(url,"POST",postData);
string text = System.Text.Encoding.ASCII.GetString(bytes);
use Fiddler to look for the parameters.