Converting HTML to PDF and attaching to email .NET - asp.net

Question

I am looking to use PDFSharp to convert a HTML page into a PDF. This then is attached into an email and sent all in one go.
So, I have a aspx page and vb code file in which gets called through a database SQL job.
Protected Sub Page_Load(sender As Object, e As EventArgs) Handles Me.Load
Dim ReqUrl As String, WorkflowID As String = String.Empty
Using con As New SqlConnection(GlobalVariables.ConStr)
Using com As New SqlCommand("EXEC App.GetWorkflowToSend", con)
con.Open()
Using dr = com.ExecuteReader
Try
While dr.Read
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12
ReqUrl = HttpContext.Current.Request.Url.GetLeftPart(UriPartial.Authority) + dr.Item("WorkflowLink")
WorkflowID = dr.Item("WorkflowID")
Dim r As String = HttpContext.Current.Request.Url.GetLeftPart(UriPartial.Authority) + dr.Item("WorkflowLink")
Dim p As String = Server.MapPath("~\Data\Files") + "\" + WorkflowID + ".pdf"
Dim t As Thread = New Thread(CType(
Function()
ConvertHTML(r, p)
SendMail(Nothing, EmailFrom, "email#address", "New PDF Generated " + WorkflowID, r + "<br/>" + p + "<br/>" + WorkflowID, EmailUser, EmailPass, EmailHost, EmailPort, EmailSSL, "", Nothing, p)
End Function, ThreadStart))
t.SetApartmentState(ApartmentState.STA)
t.Start()
Response.Write(r + "<br>")
Response.Write(p)
End While
Catch
SendMail(Nothing, EmailFrom, "email#address", "Error: " + Err.Description, WorkflowID, EmailUser, EmailPass, EmailHost, EmailPort, EmailSSL, "", Nothing)
End Try
End Using
End Using
End Using
End Sub
In the vb code I essentially call a database stored procedure. This returns some records.
For each of these records, I am currently using HttpContext.Current.Request.Url to make up a string which is essentially the the document url.
I also then declare and specify the location as a String of where I want the converted PDF to be stored.
Public Shared Function ConvertHTML(HTMLPage As String, FileName As String) As String
Dim pngfilename As String = Path.GetTempFileName()
Dim res As String = "" ' = ok
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12
'Try
Using wb As System.Windows.Forms.WebBrowser = New System.Windows.Forms.WebBrowser
wb.ScrollBarsEnabled = False
wb.ScriptErrorsSuppressed = True
wb.Navigate(HTMLPage)
While Not (wb.ReadyState = WebBrowserReadyState.Complete)
Application.DoEvents()
End While
wb.Width = wb.Document.Body.ScrollRectangle.Width
wb.Height = wb.Document.Body.ScrollRectangle.Height
If wb.Height > 3000 Then
wb.Height = 3000
End If
' Get a Bitmap representation of the webpage as it's rendered in the WebBrowser control
Dim b As Bitmap = New System.Drawing.Bitmap(wb.Width, wb.Height)
Dim hr As Integer = b.HorizontalResolution
Dim vr As Integer = b.VerticalResolution
wb.DrawToBitmap(b, New Rectangle(0, 0, wb.Width, wb.Height))
wb.Dispose()
If File.Exists(pngfilename) Then
File.Delete(pngfilename)
End If
b.Save(pngfilename, Imaging.ImageFormat.Png)
b.Dispose()
Using doc As PdfSharp.Pdf.PdfDocument = New PdfSharp.Pdf.PdfDocument
Dim page As PdfSharp.Pdf.PdfPage = New PdfSharp.Pdf.PdfPage()
page.Width = PdfSharp.Drawing.XUnit.FromInch(wb.Width / hr)
page.Height = PdfSharp.Drawing.XUnit.FromInch(wb.Height / vr)
doc.Pages.Add(page)
Dim xgr As PdfSharp.Drawing.XGraphics = PdfSharp.Drawing.XGraphics.FromPdfPage(page)
Dim img As PdfSharp.Drawing.XImage = PdfSharp.Drawing.XImage.FromFile(pngfilename)
xgr.DrawImage(img, 0, 0)
doc.Save(FileName)
doc.Close()
img.Dispose()
xgr.Dispose()
End Using
End Using
Return res
End Function
I run the conversion function with these two strings and finally call a mailing function.
PDF Error
The problem I am having at the moment is the attached PDF I receive in the email doesn't contain the correct output and states 'Navigation to the webpage was cancelled'.
http://127.0.0.1/PDF/TTR/4
C:\inetpub\wwwroot\Prod\Data\Files\4.pdf
I also sent the two strings as output within the email and they look ok.
I'm sure there is something small missing whether that be in my conversion function or just in the main code file.