FormsAuthentication.GetRedirectUrl only get the first parameter of querystring

I found the issue with FormsAuthentication.GetRedirectUrl when it redirects then it redirects with the first querystring that you have while in fact you might have more than one querystring

e.g http://localhost/myweb/login.aspx?returnurl=myview.aspx?viewID=123&viewname=abc&viewall=false then the standard FormsAuthentication will redirect to http://localhost/myweb/myview.aspx?viewID=123

but where’s the remaining viewname querystring and viewall querystring??to fix this, just use the code below to pick the remaining querystring

Methods:

  'this is used to fix the issue with FormsAuthentication.GetRedirectUrl only pick the first query string
            'get the original Redirect URL
            Dim redirectUrl As StringBuilder = New StringBuilder(FormsAuthentication.GetRedirectUrl(" ", True))
            Dim coll As NameValueCollection = objRequest.QueryString

            'iterate through every key in query string
            'add the missing query string
            For Each key As String In coll.AllKeys
                If (String.Compare(key, "returnurl", True)  0) Then
                    Dim values As String() = coll.GetValues(key)

                    If (values.Length > 0) Then
                        Dim pair As String = String.Format("{0}={1}", key, values(0))

                        If (redirectUrl.ToString().IndexOf(pair) < 0) Then
                            redirectUrl.Append("&" + pair)
                        End If
                    End If
                End If
            Next

            'this is to retain the original URL as in the query string
            objResponse.Redirect(redirectUrl.ToString())