C# .NET windows form application (store rest API authenticate)?

[perhapscwk]

i use below to authenticate a application thru REST API
(click button1).
It success, however, after that, I click button2 and
want to get data thru button 2, but it still return me 401 but I have authenticate thru button 1 already.
how to store the authenticate to C# .net (windows form application)?

below is info from the rest api manual,
Client sends a valid Basic Authentication header to the authentication point. BTW I can get the LWSSO_COOKIE_KE Y but how to use it for another web request to access other data

GET /qcbin/authentication-point/authenticate
Authorization: Basic ABCDE123

Server validates the Basic authentication headers, creates a new LW-SSO token and returns it as LWSSO_COOKIE_KE Y.

HTTP/1.1 200 OK
Set-Cookie: LWSSO_COOKIE_KE Y={cookie}

he application can now access data and services using the token. At the end of the session, log off to discard the token.

private void button1_Click(object sender, EventArgs e)
        {
try
            {
                Uri uri = new Uri("http://localhost:8080/qcbin/authentication-point/authenticate");
                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);
                request.Method = "POST";
                NetworkCredential credentials = new NetworkCredential("user", "password");
                request.Credentials = credentials;

                WebResponse v = request.GetResponse();
                Stream rStream = v.GetResponseStream();
                StreamReader str = new StreamReader(rStream);
                if (str.EndOfStream != true)
                {
                    richTextBox1.Text = str.ReadToEnd();

                }
                v.Close();
                rStream.Close();
                str.Close();
                richTextBox1.Text = "success";

            }

            catch (Exception ex)
            {
                MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK);
            }     
        }

button 2

private void button2_Click_1(object sender, EventArgs e)
        {

            HttpWebRequest request
                = WebRequest.Create("http://localhost:8080/qcbin/rest/domains/DEFAULT/projects/demoproject/defects") as HttpWebRequest;

            // Get response  
            using (HttpWebResponse response = request.GetResponse() as HttpWebResponse)
            {
                // Get the response stream  
                StreamReader reader = new StreamReader(response.GetResponseStream());

                // output  
                 richTextBox1.Text = reader.ReadToEnd();
            }  
            
            
        }

[ddikman]

I know this is old but in case someone comes across it again, I used these simple snippets:

private void Authenticate()
{
	var request = WebRequest.Create(_connectionInfo.Url + "/authentication-point/authenticate");
	var auth = Encoding.UTF8.GetBytes(_connectionInfo.Username + ":" + _connectionInfo.Password);
	request.Headers[HttpRequestHeader.Authorization] = "Basic " + Convert.ToBase64String(auth);

	var response = request.GetResponse();
	_cookie = response.Headers["Set-Cookie"];
}

private XElement GetXml(string urlPart)
{
	var url = _connectionInfo.Url + string.Format("/rest/domains/{0}/projects/{1}/{2}", _connectionInfo.Domain, _connectionInfo.Project, urlPart);
	using (var client = new WebClient())
	{
		client.Headers[HttpRequestHeader.Cookie] += ";" + _cookie;
		var response = client.DownloadString(url);
		return XDocument.Parse(response).Root;
	}
}