Web Forms :: Export Selected Records To PDF In GridView

I originally, I used most of the code from this link: URL....to allow our users the ability to check one or more checkboxes, grab data from the checked boxes and append them into a url.This works a treat.Here is code snippet.

Protected Sub btnGetChecked_Click(ByVal sender As Object, ByVal e As EventArgs)
Response.AddHeader("content-disposition", "attachment; filename=Parcels.pdf")
HttpContext.Current.Response.ContentType = "application/pdf"
Dim doc As New PdfDocument()

[Code] .....

Above code was based on link above.Then our users were having problem preserving checked boxes when navigating to other pages since we are using paging.Then I was fortunate to your article for preserving checkboxes from the link below: URL...Does anyone know how to modify it to use new code from this link?My guess is that it needs to be modified to work with the following code but I am not sure what to change.

For i As Integer = 0 To GridView1.Rows.Count - 1

If GridView1.Rows(i).RowType = DataControlRowType.DataRow Then
Dim chk As CheckBox = _
DirectCast(GridView1.Rows(i).Cells(0) _
.FindControl("CheckBox1"), CheckBox)

[code]...