(adsbygoogle = window.adsbygoogle || []).push({}); Browsing on the web i found this function:

    Public Function PostData(ByRef data As String, ByRef url As String) As String

	Dim request As HttpWebRequest = DirectCast(WebRequest.Create(url), HttpWebRequest)

	request.Method = "POST"

	request.ContentType = "application/x-www-form-urlencoded"

	Dim postData As String = data

	request.ContentLength = postData.Length



	Dim writer As New StreamWriter(request.GetRequestStream(), System.Text.Encoding.ASCII)

	writer.Write(postData)

	writer.Close()



	Dim stream As Stream = request.GetResponse().GetResponseStream()

	Dim reader As New StreamReader(stream)

	Dim response As String = String.Empty

	While (response = reader.ReadLine()) IsNot Nothing

		response += reader.ReadLine()

	End While



	Return response

End Function

I saw also that i can use it for example to sign up on youtube.
In this case i have to "post" (send) some strings to the link, example:

    Dim Request As Object = .GetResponse("https://accounts.google.com/NewAccount")

Dim Response As HttpWebResponse = DirectCast(Request, HttpWebResponse)

Dim Html As String = .ProcessResponse(Response)

Dim sb As New StringBuilder

                    sb.Append("email=" & .UrlEncode(Information.EMail))

                    sb.Append("&username=" & .UrlEncode(Information.Username))

                    sb.Append("&country=" & Information.Location)

                    sb.Append("&postal_code=" & Information.Postal)

                    sb.Append("&birthday_mon=" & Information.Birthday.Month)

                    sb.Append("&birthday_day=" & Information.Birthday.Day)

                    sb.Append("&birthday_yr=" & Information.Birthday.Year)

                    sb.Append("&gender=" & IIf(Information.Gender = Gender.Male, "m", "f"))

                    sb.Append("&find_me_via_email=agreed")

                    sb.Append("&scr=h%3D1024%26w%3D1280%26d%3D24")

                    sb.Append("&service_key=")

                    sb.Append("&session_key=")

                    sb.Append("&current_form=signupForm")

                    sb.Append("&next=%2F")

                    sb.Append("&session_token=" & .UrlEncode(.ParseBetween(Html, "XSRF_TOKEN': '", "'", "XSRF_TOKEN': '".Length).Trim))

Request = .GetResponse("https://www.youtube.com/create_account?action_save_user_info=true", sb.ToString)

Here it sends to the server some strings that contains the fields of the registration or...the data lines that the server expects to recive
now the question: How to understand what i have to "post" if i wish to create a httpwebrequest for another website?

You need to LOG the post data with a extension like tamper data for firefox or a program like fiddler. Then modify the code above to what it has.

MoBaTeY is right, most people just look at the data and get the fields from there. But this method might not actually work on all websites, especially ones that heavily use AJAX as it won't be able to execute client-side scripts - the WebBrowser control would be the easiest and most maintainable solution or you could look for another framework/control that has support for those features.

thanks, i succeeded in it using tamper data i made a tool that shorts your link with goo.gl, adf . ly, adfoc. us and tiny. cc

Yeah, made one of those before except I made a dll do others can include it in their projects.