You can use
HttpWebRequest to implement your requirement, and append all the values you want to post into a single string for the request. Here is the code snippet:
In windows app:
HttpWebRequest request = (HttpWebRequest)WebRequest.Create("https://www.yoursite.com");
request.Method = "POST";
formContent = "FormValue1=" + someValue +
"&FormValue2=" + someValue2 +
"&FormValue=" + someValue2;
byte[] byteArray = Encoding.UTF8.GetBytes(formContent);
request.ContentType = "application/x-www-form-urlencoded";
request.ContentLength = byteArray.Length;
Stream dataStream = request.GetRequestStream();
dataStream.Write(byteArray, 0, byteArray.Length);
dataStream.Close();
WebResponse response = request.GetResponse();
dataStream = response.GetResponseStream();
StreamReader reader = new StreamReader(dataStream);
string responseFromServer = HttpUtility.UrlDecode(reader.ReadToEnd());
reader.Close();
dataStream.Close();
response.Close();
In VB page load method:
Protected Sub Page_Load(sender As Object, e As EventArgs)
For Each key As String In HttpContext.Current.Request.Form.AllKeys
Dim value As String = HttpContext.Current.Request.Form(key)
Next
End Sub