I have a simple button event handler in ASP.NET that allows the user to download a spreadsheet to their browser and at the same time displays a set of controls relating to futher processing of that spreadsheet. The code is below:
Protected Sub btnDownLoadReview_Click(sender As Object, e As EventArgs) Handles btnDownLoadReview.Click
Dim excelEngine As ExcelEngine = New ExcelEngine()
Dim mboXLS() As Byte = Session("ScrubDataExcel")
Dim stream As Stream = New MemoryStream(mboXLS)
Dim workBookFinal As IWorkbook = excelEngine.Excel.Workbooks.Open(stream)
Dim fileName As String = UniqueFileName(".xls")
Dim sURL As String = ConfigurationManager.AppSettings("UploadFileName").ToString() & "_" & fileName
lblDoYouWishToModify.Visible = True
btnUploadCorrections.Visible = True
fupSelectFile.Visible = True
btnUploadCorrections.Visible = True
lblYouMayResubmit.Visible = True
workBookFinal.SaveAs(HttpContext.Current.Server.MapPath(sURL))
Response.ContentType = "application/xls"
Response.AppendHeader("Content-Disposition", "attachment; filename=" + sURL)
Response.TransmitFile(Server.MapPath(sURL))
Response.End()
End Sub
The problem seems to be the presence of the Reponse object invocations. If I remove these 4 lines, the controls display. If I refer to even one of them the controls do not display. No error is thrown but it seems as if the Visible property settings are ignored.
I tried moving the Visible settings to positions before and after the Reponse settings but to no avail.
Any ideas as to what could be wrong here?
Thanks
Carl
Related
I have found good information on how to automatically download a file to the client advertised as a solution of how to print using code
(https://forums.asp.net/t/1233841.aspx?How+do+I+print+from+Reporting+Services+AUTOMATICALLY+in+VB+Net+web+app+)
but what I need to do is have the code print the document without the user interacting.
From what I have found it appears this can not be done as one might casually think. ReportViewer for example does not have a 'print' method.
The only two solutions appears to be to use ProcessStart (which then means saving the file to the file system before printing which I dont want to do)
or maybe (will be researching this today) create a subscription using code and then delete it later.
You are not able to print a report directly from your asp.net page. The reason for this is security. If it allowed you to send a file through the network and onto the clients computer, and then search the computer for a printer, this could cause major security issues. The report viewer does have a print icon, but this disappears when you deploy the project and run the page remotely. I have faced the same issue in the past and found it best to just export the report to say PDF and allow the user to Download it. I have used the below code to accomplish this task in the past:
Private Sub CreatePDFMatrix(fileName As String)
' ReportViewer1.LocalReport.DataSources.Clear()
Dim adapter As New ReportDataSetTableAdapters.vwPrintTagsTableAdapter
Dim table As New ReportDataSet.vwPrintTagsDataTable
Dim month = MonthName(Date.Today.Month)
Dim year = Date.Today.Year
Dim p(1) As ReportParameter
Dim warnings() As Warning
Dim streamIds As String()
Dim mimeType As String = String.Empty
Dim encoding As String = String.Empty
Dim extension As String = String.Empty
Dim adpt2 As New ReportDataSetTableAdapters.vwPrintTagsTableAdapter
adapter.FillForMainReport(table, DropDownList1.SelectedValue, g_Company, g_Division)
Me.ReportViewer1.LocalReport.DataSources.Add(New ReportDataSource("DataSet1", CType(table, DataTable))) 'Add(New ReportDataSource("ReportingData", CType(table, DataTable)))
Me.ReportViewer1.DataBind()
Dim viewer = ReportViewer1
viewer.ProcessingMode = ProcessingMode.Local
viewer.LocalReport.ReportPath = "Report1.rdlc"
p(0) = New ReportParameter("MonthYear", month & "-" & year)
Dim check = DropDownList1.SelectedValue
ReportViewer1.LocalReport.SetParameters(p(0))
p(1) = New ReportParameter("Location", DropDownList1.SelectedValue)
ReportViewer1.LocalReport.SetParameters(p(1))
Try
Dim bytes As Byte() = viewer.LocalReport.Render("PDF", Nothing, mimeType, encoding, ".pdf", streamIds, warnings)
Response.Buffer = True
Response.Clear()
Response.ContentType = mimeType
Response.AddHeader("content-disposition", Convert.ToString((Convert.ToString("attachment; filename=") & fileName) + ".") & extension)
Response.BinaryWrite(bytes)
' create the file
Response.Flush()
Catch ex As Exception
Debug.Print(ex.ToString)
End Try
End Sub
I've seen several questions relating to downloading a PDF from a Web browser using Response, but none seem to fit the mysterious issue I'm having.
I am working on a project that requires the user to be able to click a button (btnPDF) to instantly download a PDF of a Telerik report with a specific "ID" string to the Downloads folder. This process was originally located in an ASPX Page on an IIS separate from where the button is located. When btnPDF was clicked, I used Response.Redirect to download the PDF through that page. The code to download the PDF looked like this:
Response.Clear()
Response.ContentType = result.MimeType 'this is always "application/pdf"
Response.Cache.SetCacheability(HttpCacheability.Private)
Response.Expires = -1
Response.Buffer = True
Response.AddHeader("Content-Disposition", String.Format("{0};FileName={1}", "attachment", fileName))
Response.BinaryWrite(result.DocumentBytes)
Response.End()
Note that result.DocumentBytes is a byte array containing correct bytes for the PDF.
This code worked fine. Now, instead of having the process on a separate Page in a separate project, I need to merge the process onto the same page where btnPDFis located, so that when you click btnPDF, a subroutine is called that performs the same task. I thought this would be very easy, pretty much a copy and paste. With the same code added in a new subroutine, this is what my click event handler "ButtonPDF_Click" now looks like:
Protected Sub ButtonPDF_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnPDF.Click
DownloadReportPDF(Me.RadGrid1.SelectedValue.ToString())
Dim strMessage As String = "alert('Printed PDF Sheet.');"
ScriptManager.RegisterStartupScript(Me, Me.GetType, "MyScript", strMessage, True)
End Sub
Protected Sub DownloadReportPDF(ByVal releaseMasterId As String)
'Service call to generate report source
Dim service As New TelerikReportLibrary.ReportServices.PPSReportService
Dim source As Telerik.Reporting.TypeReportSource = service.GetReportSource(releaseMasterId)
'Render PDF and download
Dim reportProcessor As New ReportProcessor()
Dim result As RenderingResult = reportProcessor.RenderReport("PDF", source, Nothing)
Dim fileName As String = result.DocumentName + "_" + releaseMasterId + "." + result.Extension
Response.Clear()
Response.ContentType = result.MimeType 'this is always "application/pdf"
Response.Cache.SetCacheability(HttpCacheability.Private)
Response.Expires = -1
Response.Buffer = True
Response.AddHeader("Content-Disposition", String.Format("{0};FileName={1}", "attachment", fileName))
Response.BinaryWrite(result.DocumentBytes)
Response.End()
End Sub
But the PDF no longer downloads. An accurate byte array is still created, but the Response portion does not result in the PDF being downloaded from the browser. I've found that putting a call to DownloadReportPDF in the Page_Load handler on the same Page successfully generates and downloads a PDF as it did before.
I can't see any reason why this isn't working, but I'm new to ASP, and I'm not great in VB. I've tried using Response.OutputStream, Response.WriteFile, and making use of a MemoryStream, among several other things that I've lost track of. I'm hoping there's something simple, maybe some sort of property of the Page or btnPDF I could be missing. Here is the markup for btnPDF, just in case:
<asp:linkButton ID="btnPDF" CssClass="btn btn-default" runat="server" Width="115px">
<i class="fa fa-file-text" title="Edit"></i> PDF
</asp:linkButton>
What could be causing such a problem? Where should I look at this point?
Let me know if more information is needed.
Thanks,
Shane
EDIT:
I experimented with setting a session variable on btnPDF_Click, and handling the PDF download on postback. Again, a valid byte array was generated, but the HttpResponse did not cause the PDF to download from the browser.
EDIT:
Building on the last edit, this tells me that calling DownloadReportPDF from Page_Load works only when IsPostBack is false. I just tested this thought, and it holds true. In the above code, if I check IsPostBack at the moment I'm trying to download the PDF, it is true. Investigating further.
Alright, I finally found a solution I'm satisfied with (though I still don't understand why I can't download the PDF using Response while IsPostBack is true).
Inspired by this thread, I put the previously posted code in an HttpHandler called PDFDownloadHandler, then used Response.Redirect in the btnPDF_Click event handler to utilize PDFDownloadHandler. This article helped me a lot on that process, as it is something I have not done before.
In case anyone else runs into this problem, here is the new PDFDownloadHandler:
Imports Microsoft.VisualBasic
Imports System.Web
Imports Telerik.Reporting
Imports Telerik.Reporting.Processing
Public Class PDFDownloadHandler
Implements IHttpHandler
Public Sub ProcessRequest(ByVal context As _
System.Web.HttpContext) Implements _
System.Web.IHttpHandler.ProcessRequest
Dim request As HttpRequest = context.Request
Dim response As HttpResponse = context.Response
Dim path As String = request.Path
If path.Contains("pps.pdfdownload") Then
Dim releaseMasterId As String = request.QueryString("ID")
If releaseMasterId IsNot Nothing Then
'Service call to generate report source
Dim service As New TelerikReportLibrary.ReportServices.PPSReportService
Dim source As Telerik.Reporting.TypeReportSource = service.GetReportSource(releaseMasterId)
'Render PDF and save
Dim reportProcessor As New ReportProcessor()
Dim result As RenderingResult = reportProcessor.RenderReport("PDF", source, Nothing)
Dim fileName As String = result.DocumentName + "_" + releaseMasterId + "." + result.Extension
response.Clear()
response.ContentType = result.MimeType
response.Cache.SetCacheability(HttpCacheability.Private)
response.Expires = -1
response.Buffer = True
response.AddHeader("Content-Disposition", String.Format("{0};FileName={1}", "attachment", fileName))
response.BinaryWrite(result.DocumentBytes)
End If
End If
response.End()
End Sub
Public ReadOnly Property IsReusable() As Boolean _
Implements System.Web.IHttpHandler.IsReusable
Get
Return False
End Get
End Property
End Class
Any further insight on why the original technique did not work is greatly appreciated.
I have tired many things, searched the internet, and still I cannot figure out what is going on with this code. I still get that my docx files are corrupted, but when I do it with doc file everything is going great.
My Upload Code
Private Sub LbReqUploadAttachment1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles LbReqUploadAttachment1.Click
If FileUplReqAttachment1.HasFile Then
'Then save the attachment to the documents table
Dim type As String = Me.FileUplReqAttachment1.PostedFile.ContentType
Dim myFile As System.Web.HttpPostedFile = Me.FileUplReqAttachment1.PostedFile
Dim nFileLen As Integer = myFile.ContentLength
Dim myData(nFileLen) As Byte
myFile.InputStream.Read(myData, 0, nFileLen)
Dim DocDto As New DocumentsDto
DocDto.Month = Now.ToString("m")
DocDto.Year = Now.Year
DocDto.MimeType = type
DocDto.UploadedById = MyPage.LoggedOnUser.DtoUser.PersonId
DocDto.DocumentBytes = myData.ToArray
DocDto = MyPage.DelegateDocument.CreateDocumentsDto(DocDto)
'Update the order with the new document id
If Me.TbIntlFlagz.Checked Then
Item.AssetID = CStr(DocDto.DocumentID)
Else
Item.AssetID = "0"
End If
' Save Everything
SaveItem()
'Focus after postback
FileUplReqAttachment1.Focus()
End If
'Stay on order screen
Response.Redirect(String.Format("Default.aspx?i={0}&Item={1}", MyPage.DtoPage.PageID, Me.Item.Id))
End Sub
My download code:
Sub ProcessRequest(ByVal context As HttpContext) Implements ttpHandler.ProcessRequest
Dim docba As Byte() = docDto.DocumentBytes
Dim ext As String = Mime.GetExtensionFromMime(docDto.MimeType)
context.Response.ContentType = docDto.MimeType
If String.IsNullOrEmpty(ext) Then
'We can only use the attachment approach if we found a good extension based on the mime type
Else
Dim DispositionHeader As String
If Not context.Request.QueryString.Item("fn") Is Nothing Then
DispositionHeader = String.Format("attachment; filename={0}.{1}", AntiXss.UrlEncode(context.Request.QueryString.Item("fn")), ext)
Else
DispositionHeader = String.Format("attachment; filename={0}.{1}", AntiXss.UrlEncode("Document"), ext)
End If
context.Response.AppendHeader("Content-Disposition", DispositionHeader)
End If
context.Response.Expires = (60 * 24 * 1)
context.Response.OutputStream.Write(docba, 0, docba.Length)
context.Response.Flush()
docba = Nothing
End If
End Sub
I have tired these with no success:
Why are .docx files being corrupted when downloading from an ASP.NET page?
http://www.aspmessageboard.com/showthread.php?230778-Downloaded-docx-files-are-corrupted
https://social.msdn.microsoft.com/Forums/vstudio/en-US/88383fb2-03c6-49f5-afee-ce38497789bd/retrieving-docx-stored-in-sql-server-results-in-there-was-an-error-opening-the-file?forum=vbgeneral
I am uploading the file into a DB, and downloading the file by pressing a hyperlink. When I press the hyperlink and download the file. View at the file it is corrupted.
In VB, when declaring an array you give it the number of elements in the array. This is different from many languages where you specify the last index of the array.
For the code you show, you need to use
Dim myData(nFileLen - 1) As Byte
to make sure that you do not have an extra element in the array.
It appears that the .doc format is not sensitive to this, but .docx is.
I'm trying to scrape some schedules off of a website. the information is displayed in a GridView with paging.
The url is:
http://www.landmarkworldwide.com/when-and-where/register/search-results.aspx?prgid=0&pgID=270&crid=0&ctid=&sdt=0
My Issue is when I want to scrape pages other then #1 in the grid view.
The best post I found so far was This One, but it doesn't work and that topic is not complete. I tried to use Fiddler and Chrome to get the post data and use it, but I can't get it to work for me. Can you guys see what's missing?
Here's the code I am using. it's in VB, but you can answer in C# and I'll translate -) (sorry)
Protected Sub Page_Load(sender As Object, e As System.EventArgs) Handles Me.Load
Dim lcUrl As String = "http://www.landmarkworldwide.com/when-and-where/register/search-results.aspx?prgid=0&pgID=270&crid=0&ctid=&sdt=0"
' first, request the login form to get the viewstate value
Dim webRequest__1 As HttpWebRequest = TryCast(WebRequest.Create(lcUrl), HttpWebRequest)
Dim responseReader As New StreamReader(webRequest__1.GetResponse().GetResponseStream())
Dim responseData As String = responseReader.ReadToEnd()
responseReader.Close()
' extract the viewstate value and build out POST data
Dim viewState As String = ExtractViewState(responseData)
Dim loHttp As HttpWebRequest = DirectCast(WebRequest.Create(lcUrl), HttpWebRequest)
' *** Send any POST data
Dim lcPostData As String = [String].Format("__VIEWSTATE={0}&__EVENTTARGET={1}&__EVENTARGUMENT={2}", viewState, HttpUtility.UrlEncode("contentwrapper_0$maincontent_0$maincontentfullwidth_0$ucSearchResults$gvPrograms"), HttpUtility.UrlEncode("Page$3"))
loHttp.Method = "POST"
Dim lbPostBuffer As Byte() = System.Text.Encoding.GetEncoding(1252).GetBytes(lcPostData)
loHttp.ContentLength = lbPostBuffer.Length
Dim loPostData As Stream = loHttp.GetRequestStream()
loPostData.Write(lbPostBuffer, 0, lbPostBuffer.Length)
loPostData.Close()
Dim loWebResponse As HttpWebResponse = DirectCast(loHttp.GetResponse(), HttpWebResponse)
Dim enc As Encoding = System.Text.Encoding.GetEncoding(1252)
Dim loResponseStream As New StreamReader(loWebResponse.GetResponseStream(), enc)
Dim lcHtml As String = loResponseStream.ReadToEnd()
loWebResponse.Close()
loResponseStream.Close()
Response.Write(lcHtml)
End Sub
Private Function ExtractViewState(s As String) As String
Dim viewStateNameDelimiter As String = "__VIEWSTATE"
Dim valueDelimiter As String = "value="""
Dim viewStateNamePosition As Integer = s.IndexOf(viewStateNameDelimiter)
Dim viewStateValuePosition As Integer = s.IndexOf(valueDelimiter, viewStateNamePosition)
Dim viewStateStartPosition As Integer = viewStateValuePosition + valueDelimiter.Length
Dim viewStateEndPosition As Integer = s.IndexOf("""", viewStateStartPosition)
Return HttpUtility.UrlEncodeUnicode(s.Substring(viewStateStartPosition, viewStateEndPosition - viewStateStartPosition))
End Function
To make it work you need to send all input fields to the page, not only viewstate. Other critical data is the __EVENTVALIDATION for example that you do not handle it. So:
First you need to make scrape on the #1 page. So load it and use the Html Agility Pack to convert it to a usable struct.
Then extract from that struct the input data that you need to post. From this answer HTML Agility Pack get all input fields here is a code sniped on how you can do that.
foreach (HtmlNode input in doc.DocumentNode.SelectNodes("//input"))
{
// use this to create the post string
// input.Attributes["value"];
}
Then when you have the post data that is needed to be a valid post, you move to the next step. Here is an example How to pass POST parameters to ASP.Net web request?
You can also read: How to use HTML Agility pack
I just noticed it last night,
Anyway, let's get to the interesting case here.
I have a ButtonField within DataGrid, and if you notice it here...
The Interface of that ButtonField is looks like a LINK.
But if we hover on it, it appeared as Javascript's call.
Here is the Image ScreenShot
Ya, that's the 1st case.
IT IS a javascript's call.
I didnt notice about it lately. (hehehe).
Then, if we click on that... it would call the createPDF() function. The function behind the scene (which I'm using VB.net) is to execute these code;
Protected Sub createPDF()
Dim document As New Document()
Dim mem As LengthFixingStream = New LengthFixingStream()
' instantiate a iTextSharp.text.pdf.Document
'Dim mem As New MemoryStream()
' PDF data will be written here
PdfWriter.GetInstance(document, mem)
' tie a PdfWriter instance to the stream
document.Open()
Dim titleFont = FontFactory.GetFont("Arial", 18, Font.BOLD)
document.Add(New Paragraph("Northwind Traders Receipt", titleFont))
document.Close()
' automatically closes the attached MemoryStream
Dim docData As Byte() = mem.GetBuffer()
' get the generated PDF as raw data
' write the document data to response stream and set appropriate headers:
Response.AppendHeader("Content-Disposition", "attachment; filename=testdoc.pdf")
Response.ContentType = "application/pdf"
Response.BinaryWrite(docData)
Response.[End]()
End Sub
But somehow... this of course would not deliver the PDF into the browser.
BEcause It's called by Javascript, nor the direct as Hyperlink (normally).
Thus, I'm wondering could we get the ASP.net Call new Window,
and then redirect the createPDF() result into it?
Correct me if i'm wrong...
Here is just some mockup so you get the idea. I haven't tested this. Basically you will have to put the above code in a new page...say "receipt.aspx" and execute it on the load event...you will need to setup an id parameter...if data is being pulled from the db to generate the pdf.
on the button click add the following
Dim sb As New System.Text.StringBuilder()
sb.Append("<script language='javascript'>")
sb.Append("window.open('receipt.aspx.htm?id=123'', 'Receipt',")
sb.Append("'width=800, height=800, menubar=yes, resizable=no');<")
sb.Append("/script>")
Dim t As Type = Me.GetType()
If Not ClientScript.IsStartUpScriptRegistered(t, "PopupScript") Then
ClientScript.RegisterStartUpScript(t, "PopupScript", sb.ToString())
End If
Notice the "id=123" querystring value I am passing to receipt.aspx?
You can then call that in the receipt.aspx page like this
Dim id as String = Request.QueryString("id")
CreatePDF(id)
...shoot! Just realized you are using a Grid...the principle remains the same, just wireup the buttons on RowDataBound event.
Protected Sub GridView_RowDataBound(sender As Object, e As GridViewRowEventArgs)
If e.Row.RowType = DataControlRowType.DataRow Then
Dim Id As String = DirectCast(e.Row.Cells(0).FindControl("quotationid"), Label).Text
Dim myButton As New Button
myButton = DirectCast(e.Row.Cells(4).FindControl("btnViewReceipt"), Button)
myButton.Attributes.Add("OnClick", "window.open('receipt.aspx?id=" + id + "','Receipt','scrollbars=yes','width=800,height=800')")
End If
End Sub