<p>I'm trying to convert some code that worked great in VB, but I can't figure out what objects to use in .Net.  </p>

<pre><code>    Dim oXMLHttp As XMLHTTP
    oXMLHttp = New XMLHTTP
    oXMLHttp.open "POST", "https://www.server.com/path", False
    oXMLHttp.setRequestHeader "Content-Type", "application/x-www-form-urlencoded"
    oXMLHttp.send requestString 
</code></pre>

<p>Basically, I want to send an XML file to a server, then store the response that it returns.  Can anyone point me in the right direction on this?  </p>

See the following for a sample which does this:
http://www.codeproject.com/KB/dotnet/NET_Interact_j2EE.aspx
I have put the sample below. Sorry, I know it's big, but you never know how long links like this will stay valid. 
NOTE: the first version of the question didn't say in C# .NET - it just said "in .NET". (perhaps it was tagged C# and I didn't see it) Converting from VB.NET to C# is pretty easy (though unnecessary).
'This class is representing the same functionality of xmlHTTP object in MSXML.XMLHTTP.
```
```
Imports System.Net
Imports System.Web.HttpUtility

Public Class XMLHTTP
'Makes an internet connection to specified URL 
   Public Overridable Sub open(ByVal bstrMethod As String, _
     ByVal bstrUrl As String, Optional ByVal varAsync As _
     Object = False, Optional ByVal bstrUser _
     As Object = "", Optional ByVal bstrPassword As Object = "")
       Try
           strUrl = bstrUrl
           strMethod = bstrMethod

           'Checking if proxy configuration 
           'is required...(blnIsProxy value 
           'from config file)
           If blnIsProxy Then
           'Set the proxy object
               proxyObject = WebProxy.GetDefaultProxy()

               'Finding if proxy exists and if so set 
               'the proxy configuration parameters...
               If Not (IsNothing(proxyObject.Address)) Then
                   uriAddress = proxyObject.Address
                   If Not (IsNothing(uriAddress)) Then
                       _ProxyName = uriAddress.Host
                       _ProxyPort = uriAddress.Port
                   End If
                   UpdateProxy()
               End If
               urlWebRequest.Proxy = proxyObject
           End If

           'Make the webRequest...
           urlWebRequest = System.Net.HttpWebRequest.Create(strUrl)
           urlWebRequest.Method = strMethod

           If (strMethod = "POST") Then
               setRequestHeader("Content-Type", _
                   "application/x-www-form-urlencoded")
           End If

           'Add the cookie values of jessionid of weblogic 
           'and PH-Session value of webseal 
           'for retaining the same session
           urlWebRequest.Headers.Add("Cookie", str_g_cookieval)

       Catch exp As Exception
           SetErrStatusText("Error opening method level url connection")
       End Try
   End Sub
   'Sends the request with post parameters...
   Public Overridable Sub Send(Optional ByVal objBody As Object = "")
       Try
           Dim rspResult As System.Net.HttpWebResponse
           Dim strmRequestStream As System.IO.Stream
           Dim strmReceiveStream As System.IO.Stream
           Dim encode As System.Text.Encoding
           Dim sr As System.IO.StreamReader
           Dim bytBytes() As Byte
           Dim UrlEncoded As New System.Text.StringBuilder
           Dim reserved() As Char = {ChrW(63), ChrW(61), ChrW(38)}
           urlWebRequest.Expect = Nothing
           If (strMethod = "POST") Then
               If objBody <> Nothing Then
                   Dim intICounter As Integer = 0
                   Dim intJCounter As Integer = 0
                   While intICounter < objBody.Length
                     intJCounter = _
                       objBody.IndexOfAny(reserved, intICounter)
                     If intJCounter = -1 Then
UrlEncoded.Append(System.Web.HttpUtility.UrlEncode(objBody.Substring(intICounter, _
                                                    objBody.Length - intICounter)))
                       Exit While
                     End If
UrlEncoded.Append(System.Web.HttpUtility.UrlEncode(objBody.Substring(intICounter, _
                                                        intJCounter - intICounter)))
                     UrlEncoded.Append(objBody.Substring(intJCounter, 1))
                     intICounter = intJCounter + 1
                   End While

                   bytBytes = _
                     System.Text.Encoding.UTF8.GetBytes(UrlEncoded.ToString())
                   urlWebRequest.ContentLength = bytBytes.Length
                   strmRequestStream = urlWebRequest.GetRequestStream
                   strmRequestStream.Write(bytBytes, 0, bytBytes.Length)
                   strmRequestStream.Close()
                Else
                    urlWebRequest.ContentLength = 0
               End If
           End If
           rspResult = urlWebRequest.GetResponse()
           strmReceiveStream = rspResult.GetResponseStream()
           encode = System.Text.Encoding.GetEncoding("utf-8")
           sr = New System.IO.StreamReader(strmReceiveStream, encode)

           Dim read(256) As Char
           Dim count As Integer = sr.Read(read, 0, 256)
           Do While count > 0
               Dim str As String = New String(read, 0, count)
               strResponseText = strResponseText & str
               count = sr.Read(read, 0, 256)
           Loop
       Catch exp As Exception
           SetErrStatusText("Error while sending parameters")
           WritetoLog(exp.ToString)
       End Try
   End Sub
   'Setting header values...
   Public Overridable Sub setRequestHeader(ByVal bstrHeader _
                         As String, ByVal bstrValue As String)
       Select Case bstrHeader
            Case "Referer"
                urlWebRequest.Referer = bstrValue
            Case "User-Agent"
                urlWebRequest.UserAgent = bstrValue
            Case "Content-Type"
                urlWebRequest.ContentType = bstrValue
            Case Else
                urlWebRequest.Headers(bstrHeader) = bstrValue
       End Select
   End Sub

   Private Function UpdateProxy()
       Try
           If Not (IsNothing(uriAddress)) Then
               If ((Not IsNothing(_ProxyName)) And _
                 (_ProxyName.Length > 0) And (_ProxyPort > 0)) Then
                   proxyObject = New WebProxy(_ProxyName, _ProxyPort)
                   Dim strByPass() As String = Split(strByPassList, "|")
                   If strByPass.Length > 0 Then
                       proxyObject.BypassList = strByPass
                   End If
                   proxyObject.BypassProxyOnLocal = True
                   If blnNetworkCredentials Then
                       If strDomain <> "" Then
                           proxyObject.Credentials = New _
                             NetworkCredential(strUserName, _
                             strPwd, strDomain)
                       Else
                            proxyObject.Credentials = New _
                              NetworkCredential(strUserName, _
                              strPwd)
                       End If
                   End If
               End If
           End If
       Catch exp As Exception
           SetErrStatusText("Error while updating proxy configurations")
           WritetoLog(exp.ToString)
       End Try
   End Function
   'Property for setting the Responsetext
   Public Overridable ReadOnly Property ResponseText() As String
       Get
           ResponseText = strResponseText
       End Get
   End Property

   Private urlWebRequest As System.Net.HttpWebRequest
   Private urlWebResponse As System.Net.HttpWebResponse
   Private strResponseText As String
   Private strUrl As String
   Private strMethod As String
   Private proxyObject As WebProxy
   Private intCount As Integer
   Private uriAddress As Uri
   Private _ProxyName As String
   Private _ProxyPort As Integer
End Class
```
```