SelectPdf for .NET - Start Conversion from Javascript - VB.NET / ASP.NET MVC Sample

This sample shows how to manually start the html to pdf conversion of the SelectPdf Library for .NET using a Javascript call.

SelectPdf exposes a global Javascript variable called selectpdf in the page that is being converted. Using this variable you can check if the javascript code is executed inside the converter (check if typeof(selectpdf) == "object"). The converter version can also be checked using selectpdf.version.

The most important feature of the Javascript interface is the possibility to manually start the page conversion to pdf with a javascript call. To do that, you must:
1. Set converter.Options.StartupMode = StartupMode.Manual
2. Call selectpdf.start() from javascript

- If converter.Options.StartupMode is set to StartupMode.Manual and selectpdf.start() is not called from javascript, the conversion will timeout.
- If converter.Options.StartupMode is set to the default value StartupMode.Automatic, the conversion will start without waiting for any javascript calls.

Below it's the link to a test page that waits for 3 seconds after it loads and then calls the javascript conversion method. Converting it in StartupMode.Manual mode will display the time elapsed. Converting it in StartupMode.Automatic mode will not show that 3 seconds time interval.

Test Page


Conversion start mode:


Sample Code VB.NET

Imports SelectPdf

Namespace Controllers
    Public Class ConvertFromJsController
        Inherits Controller

        ' GET: ConvertFromJs
        Public Function Index() As ActionResult
            Dim url As String = System.Web.VirtualPathUtility.
            ViewData.Add("ViewTxtUrl", (New Uri(Request.Url, url)).AbsoluteUri)

            ViewData.Add("ViewTxtHref", url)
            ViewData.Add("ViewDdlStartupModeSel", "Manual")

            Dim DdlStartupMode As New List(Of SelectListItem)()
            DdlStartupMode.Add(New SelectListItem() With {
                 .Text = "Automatic",
                 .Value = "Automatic",
                 .Selected = ViewData("ViewDdlStartupModeSel") IsNot Nothing _
                    AndAlso ViewData("ViewDdlStartupModeSel").ToString() = "Automatic"
            DdlStartupMode.Add(New SelectListItem() With {
                 .Text = "Manual",
                 .Value = "Manual",
                 .Selected = ViewData("ViewDdlStartupModeSel") IsNot Nothing _
                    AndAlso ViewData("ViewDdlStartupModeSel").ToString() = "Manual"
            ViewData.Add("ViewDdlStartupMode", DdlStartupMode)
            Return View()
        End Function

        Public Function SubmitAction(collection As FormCollection) As ActionResult
            ' instantiate a html to pdf converter object
            Dim converter As New HtmlToPdf()

            ' set startup mode
            converter.Options.StartupMode = DirectCast([Enum].Parse(
                GetType(HtmlToPdfStartupMode), collection("DdlStartupMode"), True),

            ' set timeout
            Dim timeout As Integer = 10
                timeout = Convert.ToInt32(collection("TxtTimeout"))
            End Try
            converter.Options.MaxPageLoadTime = timeout

            ' create a new pdf document converting an url
            Dim doc As PdfDocument = converter.ConvertUrl(collection("TxtUrl"))

            ' save pdf document
            Dim pdf As Byte() = doc.Save()

            ' close pdf document

            ' return resulted pdf document
            Dim fileResult As FileResult = New FileContentResult(pdf, "application/pdf")
            fileResult.FileDownloadName = "Document.pdf"
            Return fileResult
        End Function
    End Class
End Namespace