How do I know the encoding of a webpage that I read in with vb.net?

Question

I tried reading a webpage into my program using vb.net's HttpWebRequest. My problem has to do with figuring out the encoding of the web page before I actually read it into a string. When I read it in, some characters appear as diamonds with question-marks inside the diamonds. The web page itself looks fine in a browser, its just when I read it in that some characters aren't encoded right.

The original code I used was:

 Dim myWebRequest As HttpWebRequest = WebRequest.Create(ourUri) 
 Dim myWebResponse As httpWebResponse = myWebRequest.GetResponse()

Then to try to get the encoding. I used:

Dim contentType As String = myWebResponse.ContentType
Dim charset As String = myWebResponse.CharacterSet

But both 'contentType' and 'charset' end up with the value 'text/html'. What I want to know is if the webpage is encoded in 'utf-8' or some other character set, so I can later retrieve it like this:

Dim receiveStream As Stream = myWebResponse.GetResponseStream()
Dim encode As Encoding = System.Text.Encoding.GetEncoding(charset)
Using reader As StreamReader = New StreamReader(receiveStream, encode)

So to sum up, there seems to be no way to inquire what the encoding is, and then use the answer to read the webpage the right way.

Is that true? Any help is appreciated.

The entire code of the routine (asked for by a commenter) follows:

Public Shared Function DownloadFileUsingURL(ByVal URLstring As String, ByVal descFilePathAndName As String, ByRef errorMessage As String, ByRef hadRedirect As Boolean,
                                                ByRef newURL As String, ByRef isSecureConnection As Boolean, ByVal didSupplyfullfilename As Boolean, ByRef downloadedcontent As String,
                                                ByRef httpTohttps As Boolean, ByRef httpsTohttp As Boolean, ByRef BytesRead As Integer) As Boolean
    Dim ourUri As New Uri(URLstring)
    Dim csh As New ClassSyncHttp
    Dim expectSecureConnection As Boolean
    Dim domainchanged As Boolean

    newURL = ""
    errorMessage = ""
    hadRedirect = False
    httpTohttps = False
    httpsTohttp = False
    isSecureConnection = False
    If URLstring.ToLower.StartsWith("https:") Then
        ServicePointManager.Expect100Continue = True
        ServicePointManager.SecurityProtocol = SecurityProtocolType.SystemDefault
        expectSecureConnection = True
    Else
        ServicePointManager.SecurityProtocol = SecurityProtocolType.SystemDefault
        expectSecureConnection = False
    End If
    Try
        Dim myWebRequest As HttpWebRequest = WebRequest.Create(ourUri) ' I changed webrequest to httpwebrequest
        Dim cookieContainer As CookieContainer = New CookieContainer   ' needs httpwebrequest to work

        myWebRequest.CookieContainer = cookieContainer
        myWebRequest.Proxy.Credentials = System.Net.CredentialCache.DefaultCredentials
        myWebRequest.UserAgent = "BrowseNet"
        myWebRequest.Timeout = ClassGlobalVariables.downloadTimeoutMilliseconds
        myWebRequest.Credentials = CredentialCache.DefaultCredentials
        Dim myWebResponse As HttpWebResponse = myWebRequest.GetResponse()
        Dim contentType As String = myWebResponse.ContentType
        Dim charset As String = myWebResponse.CharacterSet

        If Not ourUri.Equals(myWebResponse.ResponseUri) Then
            newURL = myWebResponse.ResponseUri.ToString
            hadRedirect = True
            If newURL.ToLower.StartsWith("https") Then
                isSecureConnection = True
            End If
            compareURLs(URLstring, newURL, httpTohttps, domainchanged)
        End If

        Dim receiveStream As Stream = myWebResponse.GetResponseStream()

        If didSupplyfullfilename Then
            Using fs As FileStream = File.Create(descFilePathAndName)
                receiveStream.CopyTo(fs)
                BytesRead = fs.Length
            End Using
        Else
            Dim encode As Encoding = System.Text.Encoding.GetEncoding(charset)
            Using reader As StreamReader = New StreamReader(receiveStream, encode)
                '   receiveStream.Seek(0, SeekOrigin.Begin)
                downloadedcontent = reader.ReadToEnd()
                BytesRead = downloadedcontent.Length
            End Using
        End If
        myWebResponse.Close()

        If expectSecureConnection Then
            isSecureConnection = True
        Else
            isSecureConnection = False
        End If

        Return True
    Catch ex As webException
        If expectSecureConnection Then
            ' guessing here that the problem was that was wrong about secure connection.   (Problem could be elsewhere, of course)
            isSecureConnection = False
            httpsTohttp = True
            If ex.HResult = System.Net.WebExceptionStatus.SecureChannelFailure Then
                ' not sure what to do
            End If
            'Else
            '    isSecureConnection = True
        End If
        errorMessage = ex.Message

        Return False
    End Try


End Function