using System;
using System.Collections.Generic;
using System.Windows.Forms;
using System.Net.Http;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Login();
        }

        public void Login()
        {
            var baseURL = "https://hisweb.fh-nordhausen.de";
            var loginURL = "/qisserver/rds";
            var user = "xxx";
            var pass = "xxx";

            var client = new HttpClient();
            try
            {
                client.BaseAddress = new Uri(baseURL);

                var values = new List<KeyValuePair<string, string>>();

                values.Add(new KeyValuePair<string, string>("asdf", user));
                values.Add(new KeyValuePair<string, string>("fdsa", pass));
                FormUrlEncodedContent content = new FormUrlEncodedContent(values);

                var response = client.PostAsync(loginURL, content).Result;
                var contents = response.Content.ReadAsStringAsync();

                Console.WriteLine(response.Content);
                Console.WriteLine(response.StatusCode);
            }
            catch (AggregateException ex)
            {
                foreach (var item in ex.Flatten().InnerExceptions)
                {
                    Console.WriteLine(item.Message);
                }
            }
        }
    }
}