如何正确发布请求

Question

我正在尝试使用HttpWebRequest发出发布请求，并使用html敏捷包加载html。我有以下两种方法。

因此，当我运行代码时，它会向我返回htmldocument，但它是原始url html，就像从未发出过post请求一样。

 public static async Task<HtmlDocument> GetDavaTest(string cookie,string url)
    {


        var sb = new StringBuilder();
        AppendParameter(sb, "DropDownList1", "1");
        AppendParameter(sb, "DropDownList2", "Tümü");
        AppendParameter(sb, "DropDownList3", "Baslatan");
        AppendParameter(sb, "DropDownList4", "2019");
        AppendParameter(sb, "DropDownList5", "Tümü");
        AppendParameter(sb, "Button1", "Sorgula");


        var byteArray = Encoding.UTF8.GetBytes(sb.ToString());

        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
        request.CookieContainer = new CookieContainer();
        request.CookieContainer.SetCookies(new Uri(url), cookie);
        request.Method = "POST";
        request.ContentType = "application/x-www-form-urlencoded";
        request.ContentLength = byteArray.Length;


        using (var stream = request.GetRequestStream())
        {
            await stream.WriteAsync(byteArray, 0, byteArray.Length);
        }

        using (var response = (HttpWebResponse)(await request.GetResponseAsync()))
        {
            var responseString = new StreamReader( response.GetResponseStream()).ReadToEndAsync();

            var htmlDoc = new HtmlDocument();
            htmlDoc.LoadHtml(await responseString);

            return htmlDoc;
        }


    }
    protected static void AppendParameter(StringBuilder sb, string name, string value)
    {
        string encodedValue = HttpUtility.UrlEncode(value);
        sb.AppendFormat("{0}={1}&", name, encodedValue);
    }