google多語翻譯，會自動判斷網頁編碼

        private void Form1_Load(object sender, EventArgs e)
        {
            DataTable dt = new DataTable();
            dt.Columns.Add("ID");
            dt.Columns.Add("Name");
            dt.Rows.Add("en", "英文");
            dt.Rows.Add("zh-TW", "中文(繁體)");
            dt.Rows.Add("zh-CN", "中文(簡體)");
            dt.Rows.Add("tr", "土耳其文");
            dt.Rows.Add("da", "丹麥文");
            dt.Rows.Add("ja", "日文");
            dt.Rows.Add("lt", "立陶宛文");
            dt.Rows.Add("hu", "匈牙利文");
            dt.Rows.Add("id", "印尼文");
            dt.Rows.Add("hi", "印度文");
            dt.Rows.Add("es", "西班牙文");
            dt.Rows.Add("ca", "西班牙加泰羅尼亞文");
            dt.Rows.Add("hr", "克羅地亞文");
            dt.Rows.Add("iw", "希伯來文");
            dt.Rows.Add("el", "希臘文");
            dt.Rows.Add("lv", "拉脫維亞文");
            dt.Rows.Add("pl", "波蘭文");
            dt.Rows.Add("fr", "法文");
            dt.Rows.Add("fi", "芬蘭文");
            dt.Rows.Add("ar", "阿拉伯文");
            dt.Rows.Add("sq", "阿爾巴尼亞文");
            dt.Rows.Add("bg", "保加利亞文");
            dt.Rows.Add("ru", "俄文");
            dt.Rows.Add("no", "挪威文");
            dt.Rows.Add("th", "泰文");
            dt.Rows.Add("uk", "烏克蘭文");
            dt.Rows.Add("mt", "馬耳他文");
            dt.Rows.Add("cs", "捷克文");
            dt.Rows.Add("nl", "荷蘭文");
            dt.Rows.Add("sl", "斯拉維尼亞文");
            dt.Rows.Add("sk", "斯洛伐克文");
            dt.Rows.Add("tl", "菲律賓文");
            dt.Rows.Add("vi", "越南文");
            dt.Rows.Add("sr", "塞爾維亞文");
            dt.Rows.Add("et", "愛沙尼亞文");
            dt.Rows.Add("gl", "愛爾蘭的蓋爾文");
            dt.Rows.Add("sv", "瑞典文");
            dt.Rows.Add("it", "義大利文");
            dt.Rows.Add("pt", "葡萄牙文");
            dt.Rows.Add("de", "德文");
            dt.Rows.Add("ko", "韓文");
            dt.Rows.Add("ro", "羅馬尼亞文");
            this.comboBox1.DataSource = dt;
            this.comboBox1.DisplayMember = "Name";
            this.comboBox1.ValueMember = "ID";
            this.comboBox1.SelectedIndex = 1;
            this.comboBox2.DataSource = dt.Copy();
            this.comboBox2.DisplayMember = "Name";
            this.comboBox2.ValueMember = "ID";
            this.comboBox2.SelectedIndex = 0;
        }
*******************************************************************************************

        // WebRequest方式 Demo
        private string TranslateByPost(string sourceWord, string fromLanguage, string toLanguage)
        {
            //POST方式實現，無長度限制
            string serverUrl = "http://translate.google.com/";
            string postData = string.Format("langpair={0}|{1}&text={2}", fromLanguage, toLanguage, HttpUtility.UrlEncode(sourceWord));

            WebRequest request = WebRequest.Create(serverUrl);
            request.Method = "POST";
            byte[] bytes = Encoding.Default.GetBytes(postData);
            request.ContentType = "application/x-www-form-urlencoded";
            request.ContentLength = postData.Length;
            Stream postStream = request.GetRequestStream();
            postStream.Write(bytes, 0, postData.Length);
            postStream.Close();

            WebResponse response = request.GetResponse();
            Encoding encoding = Encoding.GetEncoding(response.ContentType.Replace("text/html; charset=", ""));  //取得網頁編碼
            string strResult = new StreamReader(response.GetResponseStream(), encoding).ReadToEnd();  //回傳的結果
            response.Close();

            //使用正則表達式去除多餘的文字內容
            string strReg = @"\s+id=""?result_box""?\s+[^>]*>(.+)</span>\s*</div>\s*</div>\s*<div id=spell-place-holder\s+";
            Match match = Regex.Match(strResult, strReg, RegexOptions.IgnoreCase | RegexOptions.Singleline);

            string strReturn = null;
            if (match.Success)
            {
                strReturn = match.Groups[1].Value;
                strReturn = Regex.Replace(strReturn, @"<br\s*/?>", "\n", RegexOptions.Singleline | RegexOptions.IgnoreCase);
                strReturn = Regex.Replace(strReturn, @"<[^>]*>", "", RegexOptions.Singleline | RegexOptions.IgnoreCase);
                strReturn = HttpUtility.HtmlDecode(strReturn);
            }

            return strReturn;
        }
*******************************************************************************************

//開始翻譯
textBox2.Text = TranslateByPost(textBox1.Text, comboBox1.SelectedValue.ToString(), comboBox2.SelectedValue.ToString());