Set Initial Zoom Level of the Generated PDF Document

protected void convertToPdfButton_Click(object sender, EventArgs e)
{
    // Create a PDF document
    Document pdfDocument = new Document();

    // Set license key received after purchase to use the converter in licensed mode
    // Leave it not set to use the converter in demo mode
    pdfDocument.LicenseKey = "4W9+bn19bn5ue2B+bn1/YH98YHd3d3c=";

    // Add a page to PDF document
    PdfPage pdfPage = pdfDocument.AddPage();

    try
    {
        // Create a HTML to PDF element to add to document
        HtmlToPdfElement htmlToPdfElement = new HtmlToPdfElement(urlTextBox.Text);

        // Optionally set a delay before conversion to allow asynchonous scripts to finish
        htmlToPdfElement.ConversionDelay = 2;

        // Add the HTML to PDF element to document
        pdfPage.AddElement(htmlToPdfElement);

        int goToPageNumber = int.Parse(pageNumberTextBox.Text);
        if (goToPageNumber > pdfDocument.Pages.Count)
        {
            return;
        }

        // Get destination PDF page
        PdfPage goToPage = pdfDocument.Pages[goToPageNumber - 1];

        // Get the destination point in PDF page
        float goToX = float.Parse(xLocationTextBox.Text);
        float goToY = float.Parse(yLocationTextBox.Text);

        PointF goToLocation = new PointF(goToX, goToY);

        // Get the destination view mode
        DestinationViewMode viewMode = SelectedViewMode();

        // Create the destination in PDF document
        ExplicitDestination goToDestination = new ExplicitDestination(goToPage, goToLocation, viewMode);

        // Set the zoom level when the destination is displayed
        if (viewMode == DestinationViewMode.XYZ)
            goToDestination.ZoomPercentage = int.Parse(zoomLevelTextBox.Text);

        // Set the document Go To open action
        pdfDocument.OpenAction.Action = new PdfActionGoTo(goToDestination);

        // Save the PDF document in a memory buffer
        byte[] outPdfBuffer = pdfDocument.Save();

        // Send the PDF as response to browser

        // Set response content type
        Response.AddHeader("Content-Type", "application/pdf");

        // Instruct the browser to open the PDF file as an attachment or inline
        Response.AddHeader("Content-Disposition", String.Format("attachment; filename=Set_Initial_Zoom_Level.pdf; size={0}", outPdfBuffer.Length.ToString()));

        // Write the PDF document buffer to HTTP response
        Response.BinaryWrite(outPdfBuffer);

        // End the HTTP response and stop the current page processing
        Response.End();
    }
    finally
    {
        // Close the PDF document
        pdfDocument.Close();
    }
}

Protected Sub convertToPdfButton_Click(ByVal sender As Object, ByVal e As EventArgs)
    ' Create a PDF document
    Dim pdfDocument As New Document()

    ' Set license key received after purchase to use the converter in licensed mode
    ' Leave it not set to use the converter in demo mode
    pdfDocument.LicenseKey = "4W9+bn19bn5ue2B+bn1/YH98YHd3d3c="

    ' Add a page to PDF document
    Dim pdfPage As PdfPage = pdfDocument.AddPage()

    Try
        ' Create a HTML to PDF element to add to document
        Dim htmlToPdfElement As New HtmlToPdfElement(urlTextBox.Text)

        ' Optionally set a delay before conversion to allow asynchonous scripts to finish
        htmlToPdfElement.ConversionDelay = 2

        ' Add the HTML to PDF element to document
        pdfPage.AddElement(htmlToPdfElement)

        Dim goToPageNumber As Integer = Integer.Parse(pageNumberTextBox.Text)
        If goToPageNumber > pdfDocument.Pages.Count Then
            Return
        End If

        ' Get destination PDF page
        Dim goToPage As PdfPage = pdfDocument.Pages(goToPageNumber - 1)

        ' Get the destination point in PDF page
        Dim goToX As Single = Single.Parse(xLocationTextBox.Text)
        Dim goToY As Single = Single.Parse(yLocationTextBox.Text)

        Dim goToLocation As New PointF(goToX, goToY)

        ' Get the destination view mode
        Dim viewMode As DestinationViewMode = SelectedViewMode()

        ' Create the destination in PDF document
        Dim goToDestination As New ExplicitDestination(goToPage, goToLocation, viewMode)

        ' Set the zoom level when the destination is displayed
        If viewMode = DestinationViewMode.XYZ Then
            goToDestination.ZoomPercentage = Integer.Parse(zoomLevelTextBox.Text)
        End If

        ' Set the document Go To open action
        pdfDocument.OpenAction.Action = New PdfActionGoTo(goToDestination)

        ' Save the PDF document in a memory buffer
        Dim outPdfBuffer() As Byte = pdfDocument.Save()

        ' Send the PDF as response to browser

        ' Set response content type
        Response.AddHeader("Content-Type", "application/pdf")

        ' Instruct the browser to open the PDF file as an attachment or inline
        Response.AddHeader("Content-Disposition", String.Format("attachment; filename=Set_Initial_Zoom_Level.pdf; size={0}", outPdfBuffer.Length.ToString()))

        ' Write the PDF document buffer to HTTP response
        Response.BinaryWrite(outPdfBuffer)

        ' End the HTTP response and stop the current page processing
        Response.End()
    Finally
        ' Close the PDF document
        pdfDocument.Close()
    End Try
End Sub