iOS Question display pdf with canvas

Sub btn_vuerecet_Click
    Dim pdf As PDFDocument
    Dim wRecet As recette
    Dim nf As String
    If SelectedRow = -1 Then
        Msgbox("Vous devez selectionner une recette","Lucullus")
    Else
        wRecet = lisRecet.Get(SelectedRow)
        nf = "luc_" & wRecet.nom & ".pdf"
        nf = nf.Replace(" ", "_")
        pdf.Initialize(File.DirDocuments, nf)
        pnl_pdf.Visible = True
        pnl_btnrecet.UserInteractionEnabled = False
        cvs.Initialize(scrolpdf.Panel)
        cvs.DrawPDF(pdf, 1, cvs.TargetRect)
        cvs.Refresh
    End If
End Sub