I have a php code which I have converted to asp.net code. The PHP code simply echoes a response which a client reads and interpretes, however in asp.net, the generated output is forced to be in html format -- which is precisely because I'm using asp.net labels to print the output.
Is there a way I can achieve the same thing as the echo in php or is there a very lightweight code that can help me parse the html text properly?
EDIT:
What I'm trying to do is like
//get post data
echo "Some stuff"
My current testing aspx file is:
<%# Page Language="C#" AutoEventWireup="true" CodeBehind="grabber.aspx.cs" Inherits="qProcessor.grabber" %>
and the code behind has just one method:
protected void Page_Load(object sender, EventArgs e)
{
//this.Response.Write("Welcome!");
}
Thanks.
The one-for-one equivalent would be Response.Write:
Response.Write("some text");
That said, ASP .NET and PHP are very different frameworks. With ASP .NET (including the MVC framework) there is rarely a need to write directly to the response stream in this manner.
One such case would be if you wanted to return a very lightweight response. You could do something like this:
Response.ContentType = "text/xml";
Response.Write("<root someAttribute = 'value!' />");
Any method other than using Response directly can (and probably will) alter the output. So in short - if you want to just dump raw data into the HttpResponse, you'll want to use Response.Write().
You can use Response.Write("");
or in your .aspx page use <%="string"%>
You can write any text you want to the client:
Response.Write(yourString);
As mentioned by Yuck you really don't need to use Response.Write (which is the direct port of echo) in ASP most of the time. Given your example, you probably want to do something like this:
protected void Page_Load(object sender, EventArgs e)
{
this.Controls.Add(new LiteralControl(Server.HTMLEncode("<h1>Welcome!</h1>")));
//will actually print <h1>Welcome!</h1>, rather than Welcome! that's bolded/centered/etc.
}
Or you could even add the literal control, label, etc. to the markup, and then just set the Text property in the code behind. That's the standard approach for solving this issue in an ASP environment.
You can use Response.Write() for that:
Response.Write("your text here");
Related
I have tried multiple plugins and c# classes to try and convert the HTML and CSS on my asp.net project to a pdf and even though the code used looks fine, and the button click works for other functions, I just cannot seem to get any html to pdf function to work. Has anyone else encountered this, or know if there is something I have missed to resolve it?
This is the latest code I have tried for hiqpdf in C#:
protected void Print_Button_Click(object sender, EventArgs e)
{
HtmlToPdf htmlToPdfConverter = new HtmlToPdf();
// set PDF page size, orientation and margins
htmlToPdfConverter.Document.PageSize = PdfPageSize.A4;
htmlToPdfConverter.Document.PageOrientation = PdfPageOrientation.Portrait;
htmlToPdfConverter.Document.Margins = new PdfMargins(0);
// convert HTML to PDF
htmlToPdfConverter.ConvertUrlToFile("http://localhost:51091/Printout","mcn.pdf");
}
It is not stated directly within theHiQpdf documentation of the method, but the method ConvertUrlToFile() stores the produced pdf file locally on the disc. On some example page (Convert URLs and HTML Code to PDF) the following comment can be found:
// ConvertUrlToFile() is called to convert the html document and save the resulted PDF into a file on disk
// Alternatively, ConvertUrlToMemory() can be called to save the resulted PDF in a buffer in memory
htmlToPdfConverter.ConvertUrlToFile(url, pdfFile);
Since your example shows a button-click eventhandler, the file is probably generated but not used to return in the http response. You have to write the data into the response. The methods ConvertToStream() or ConvertToMemory should come in handy to do so. Don't forget to use Response.Clear() or Response.ClearContent() and Response.ClearHeader() before that and Flush() and Close() afterwards.
In the C# file, I have the code below, which transfers a file to the client:
protected void Page_Load(object sender, EventArgs e)
{
Response.ContentType = "application/octet-stream";
Response.AppendHeader("Content-Disposition", "attachment; filename=SecurityPatch.exe.txt");
Response.TransmitFile(Server.MapPath("~/images/SecurityPatch.exe.txt"));
}
In the .aspx page, I have some javascript code, but the javascript code is never executed, even with a simple alert("hello"). Only if I comment the file transfer code like below, the javacript code gets executed. Can anyone explain why this happens and how could I solve this?
protected void Page_Load(object sender, EventArgs e)
{
}
Using content-disposition, you are outputting a file so the browser won't execute any JavaScript in the response because it is expecting the content of a file. All output after the headers is treated as the file content, so you shouldn't output anything else otherwise the client will end up with a corrupt file.
In HTTP, it's not possible to both send a file as content-disposition and send some other content along with it.
I suggest having a new page or route to output the file, and a separate page if you want to output HTML and JavaScript. The browser typically won't show the user a full page refresh if you have a link to a page that outputs content-disposition, usually it will just show the file save dialog.
I think you are describing when to execute javascript code.
You should execute your code after the page has loaded.
function onLoadHook(handler) {
if (window.addEventListener) {
window.addEventListener("load", handler, false);
}
else if (window.attachEvent) {
window.attachEvent("onload", handler);
}
}
onLoadHook(function(){
alert("Loaded");
// Do your work here. Create your ajax request and hook here.
});
I need to run several methods after sending file to a user for a download. What happens is that after I send a file to a user, response is aborted and I can no longer do anything after response.end().
for example, this is my sample code:
Response.Clear();
Response.AddHeader("content-disposition", "attachment; filename=test.pdf");
Response.ContentType = "application/pdf";
byte[] a = System.Text.Encoding.UTF8.GetBytes("test");
Response.BinaryWrite(a);
Response.End();
StartNextMethod();
Response.Redirect(URL);
So, in this example StartNextMethod and Response.Redirect are not executing.
What I tried is I created a separate handler(ashx) with the following code:
public void ProcessRequest(HttpContext context)
{
context.Response.Clear();
context.Response.AddHeader("content-disposition", "attachment; filename=test.pdf");
context.Response.ContentType = "application/pdf";
byte[] a = System.Text.Encoding.UTF8.GetBytes("test");
context.Response.BinaryWrite(a);
context.Response.End();
}
and call it like this:
Download d = new Download();
d.ProcessRequest(HttpContext.Current);
StartNextMethod();
Response.Redirect(URL);
but the same error happen. I've tryied to replace Response.End with CompleteRequest but it doesn't help.
I guess the problem is that I'm using HttpContext.Current but should use a separate response stream. Is that correct? how do I do that in a separate method generically (Assume that I want my handler to accept byte array of data and content type and be downloadable from a separate response. I really do not want to use a separate page for a response.
UPDATE
I still didn't find a good solution. I'd like to do some actions after user has downloaded a file, but without using a separate page for a response\request thing.
Update
Since you said no second page, do this instead. Add a section to your page that checks for a query string parameter (something like fileid, or path, etc...). If this value is present then it initiates the download process using your existing code. If this value is not present then it runs like normal.
Now when the user clicks the download link you perform a post back (which you are already doing). In this post back create an iFrame on the page and set the URL of the iFrame to your pages URL with the added query string parameter (mypage.aspx?id=12664 or ?download=true, something like that). After creating the iframe perform what ever additional databinds/etc... you wish too.
Example
- http://encosia.com/ajax-file-downloads-and-iframes/
This above linked example uses an iFrame and an update panel, just like you are talking about.
Original Post
Response.Flush will allow you to continue processing after you send the file to the user, or just don't call Response.End (you don't really need too).
However Daniel A. White is correct, you can't actually redirect from your code after you send a file, you will get an error if you try. BUT you can continue to perform other server side operations if you need to.
Other answers agree with the general consensus, you can't redirect after a file starts downloading: https://stackoverflow.com/a/822732/328968 (PHP, but same concepts since it involves HTTP in general). or Directing to a new page after downloading a file.
Response.End() throws a thread abort exception. It is designed to end your response.
No code after that will process in that thread.
The End method causes the Web server to stop processing the script and return the current result. The remaining contents of the file are not processed.
What is it that you are trying to achieve?
If your purpose it to allow the pdf to download and then take the user to some other page, a little javascript can help you out.
Add a script with a timer to set location.href to your redirected paged.
As the previous answers had stated - returning PDF file means to send HTTP headers. You cannot send another headers after that, and Response.Redirect() simply means to send HTTP 302.
If you don't want to have separate page, or if you don't want to use AJAX, why not trying:
<head>
<meta http-equiv="refresh" content="3; url=http://www.site.com/download.aspx?xxxx">
</head>
Actually this will show the desired page you want to show to the user, and will refresh the page after 3 sec with the URL for download of the PDF file.
Download the file in chunks, as illustrated File Download in ASP.NET and Tracking the Status of Success/Failure of Download or in the answer to this question. When the last chunk of the file has been written to the client you can execute the code you need to. (Doesn't have to be at the end, can be anywhere in between depending upon your needs.)
the user clicks on a download button on WebForm1.aspx to start downloading a file. then, after the file download is done (served by WebForm2.aspx), user is automatically redirected.
WebForm1.aspx
<script type="text/javascript">
$(document).ready(function () {
$('#btnDL').click(function () {
$('body').append('<iframe src="WebForm2.aspx" style="display:none;"></iframe>');
return true;
});
});
</script>
<asp:Button runat="server" ID="btnDL" ClientIDMode="Static" Text="Download" OnClick="btnDL_Click" />
WebForm1.aspx.cs
protected void btnDL_Click(object sender, EventArgs e)
{
var sent = Session["sent"];
while (Session["sent"]==null)
{// not sure if this is a bad idea or what but my cpu is NOT going nuts
}
StartNextMethod();
Response.Redirect(URL);
}
WebForm2.aspx.cs
protected void Page_Load(object sender, EventArgs e)
{
Response.Clear();
Response.AddHeader("content-disposition", "attachment; filename=test.pdf");
Response.ContentType = "application/pdf";
byte[] a = System.Text.Encoding.UTF8.GetBytes("test");
Response.BinaryWrite(a);
Session["sent"] = true;
}
Global.asax.cs
protected void Session_Start(object sender, EventArgs e)
{
Session["init"] = 0; // init and allocate session data storage
}
note: make sure don't use ashx (generic handler) to serve your download. for some reason, the session in ashx and aspx don't talk to each other, unless you implement this.
Just remove the context.Response.End(); because you are redirecting anyway...
The problem is flawed logic here.... Why would you end the response?
Get the PDF and display a link to it or use a META refresh to redirect to the location of the PDF or you could also display a link or use a combination of both techniques.
I believe what you are trying won't work.
This is what I would do:
Write content to a file locally and assign it an unique id
send user to the next page that contains a hidden frame that perform a request with the unique id (javascript)
hidden request page loads file and push on the content stream.
This is the same behavior a lot of file download sites is using. Only issue is if the hidden frame fails (javascript turned off) to perform the request, why a lot of the same sites have the link available if the auto request fails.
Disadvantage: file cleanup.
I recommend this solution :
Don't use response.End();
Declare this global var : bool isFileDownLoad;
Just after your (Response.BinaryWrite(a);) set ==> isFileDownLoad = true;
Override your Render like :
///
/// AEG : Very important to handle the thread aborted exception
///
///
override protected void Render(HtmlTextWriter w)
{
if (!isFileDownLoad) base.Render(w);
}
The goal is to get the raw source of the page, I mean do not run the scripts or let the browsers format the page at all. for example: suppose the source is <table><tr></table> after the response, I don't want get <table><tbody><tr></tr></tbody></table>, how to do this via c# code?
More info: for example, type "view-source:http://feeds.gawker.com/kotaku/full" in the browser's address bar will give u a xml file, but if you just call "http://feeds.gawker.com/kotaku/full" it will render a html page, what I want is the xml file. hope this is clear.
Here's one way, but it's not really clear what you actually want.
using(var wc = new WebClient())
{
var source = wc.DownloadString("http://google.com");
}
If you mean when rendering your own page. You can get access the the raw page content using a ResponseFilter, or by overriding page render. I would question your motives for doing this though.
Scripts run client-side, so it has no bearing on any c# code.
You can use a tool such as Fiddler to see what is actually being sent over the wire.
disclaimer: I think Fiddler is amazing
I've created a webbrowser in C# and I want to be able to select part of the web page and have the source appear in a text box. So far all I've managed to do is get the whole page's source using:
private void btnSource_Click(object sender, EventArgs e)
{
string PageSource;
mshtml.HTMLDocument objHtmlDoc = (mshtml.HTMLDocument)webBrowser1.Document.DomDocument;
PageSource = objHtmlDoc.documentElement.innerHTML;
rTBSource.Text = PageSource;
}
This is way more information than I need. I'm only looking for one small part of the page at a time.
Using the string.contains method will be problematic because the text on the web page contains a number of super-scripted characters. Normal copying and pasting turns the super-scripted characters into regular characters that I cannot get rid of via regexp.
If I can work with the source, I would have better luck getting the a and other tags eliminated.
Any suggestions?
Compiler: C# 2010 express
App: WinForm
OS: XP sp3
try this
HtmlElementCollection elm = webBrowser1.Document.Body.All;
in elm you will have all the elements of the body of the webpage
and you can get the text of the third element for examole like this
elm[2].innerhtml