How can get page source code on post method with parameters

I would like to get result from http://cbseresults.nic.in/Jee_main_pzy/jee_cbse_2018.htm

need to give two inputs regno & dob, regno=11800184, dob=20/11/2000.

after submit we will get http://cbseresults.nic.in/Jee_main_pzy/jee_cbse_2018.asp

my request is through webclient with parameters i get result page source code.

Please help in this issue.

Thank you

i tried below code

string url="http://cbseresults.nic.in/Jee_main_pzy/jee_cbse_2018.asp";
 WebClient wc = new WebClient();             
wc.QueryString.Add("regno", "11800184");             
wc.QueryString.Add("dob", "20/11/2000");             
wc.QueryString.Add("B2", "Submit");              
var data = wc.UploadValues(url, "POST", wc.QueryString);    
var responseString = UnicodeEncoding.UTF8.GetString(data);              
TextBox1.Text = responseString;