Pastebin API

string pastebin_login_url = "http://pastebin.com/api/api_login.php";
        string pastebin_post_url = "http://pastebin.com/api/api_post.php";
        string pastebin_dev_key = "???????????????????????????";
        string _pastebinUserKey = null;

        void SendViaPasteBin() {

            string body = GetText(txtMain);

            string subject = txtSubject.Text.Trim();
            if(string.IsNullOrEmpty(subject)) {
                subject = "Note " + DateTime.Now.ToLongDateString() + ":" + DateTime.Now.ToShortTimeString();
            }

            string api_paste_format = "csharp";
            string userk = LogInToPasteBin();

            NameValueCollection values = new NameValueCollection();
            values.Add("api_dev_key",pastebin_dev_key);
            values.Add("api_option","paste");
            values.Add("api_paste_code",body);
            values.Add("api_paste_private","0");
            values.Add("api_paste_name",subject);
            values.Add("api_paste_expire_date","N");
            values.Add("api_paste_format",api_paste_format);
            values.Add("api_user_key",userk);

            using(WebClient wc = new WebClient()) {

                byte[] respBytes = wc.UploadValues(pastebin_post_url,values);
                string respString = Encoding.UTF8.GetString(respBytes);

                Uri valid = null;
                if(Uri.TryCreate(respString,UriKind.Absolute,out valid)) {
                    MessageBox.Show("Success: " + valid.ToString());
                }
                else {
                    MessageBox.Show("Error:" + respString);
                }
            }
        }

        string LogInToPasteBin() {

            if(_pastebinUserKey != null)
                return _pastebinUserKey;

            string userName = "?????????";
            string pwd = "?????????";

            NameValueCollection values = new NameValueCollection();
            values.Add("api_dev_key",pastebin_dev_key);
            values.Add("api_user_name",userName);
            values.Add("api_user_password",pwd);

            using(WebClient wc = new WebClient()) {
                byte[] respBytes = wc.UploadValues(pastebin_login_url,values);
                string resp = Encoding.UTF8.GetString(respBytes);
                if(resp.Contains("Bad API request")) {
                    MessageBox.Show("Error:" + resp);
                    return null;
                }
                _pastebinUserKey = resp;
            }
            return _pastebinUserKey;
        }