Click here to Skip to main content
Click here to Skip to main content

ASP.NET Clipboard for PDF Rasterization

, 20 Sep 2006
Rate this:
Please Sign up or sign in to vote.
Use the clipboard to rasterize and/or resize a PDF file. This allows you to also save it for use as a JPG.

Background

The first question you may ask is "Why would you ever want to use the server's clipboard to do anything?" Good question Smile | :) . I came across this problem when I was trying to write a PDF parser that would rasterize the front page and save it into a Bitmap object. From here, you can save it to a file, database, etc. To do this, I was using the Adobe Acrobat COM library that comes with Adobe Acrobat 7.0. Unfortunately, they do not have a function that allows you to simply save to a file. They do, however, let you copy the image to the clipboard and then recover it in whatever format you want.

Problem

I found some great code by Jonathan Hodgson here: Generate Thumbnail Images from PDF Documents. This code was written for a C#/VB.NET Windows app, and works great if used that way. However, when I tried to use this text in the OnClick event of an ASP.NET Button control, I found that nothing was happening. Turns out, the CopyToClipboard command was working fine, because if I traced through, I could press Ctrl+v and see the image perfectly. However, when the Clipboard.GetObject method was called, it was always returning null.

Solution

After much digging and two days of work, I stumbled on the reason: the thread started for the ASP.NET application did not have the right ApartmentState to read the Clipboard class. So, here is what I did to work around this:

protected void Button_Click(object sender, EventArgs e)
{
     Thread cbThread = new Thread(new ThreadStart(CopyToClipboard));
     cbThread.ApartmentState = ApartmentState.STA;
     cbThread.Start();
     cbThread.Join();
}

[STAThread]
protected void CopyToClipboard()
{
     /*
     In here, put the code that copies AND retrieves from the clipboard.
     If you use global variables, the Bitmap you populate 
     here can be used elsewhere in your code.
     */
}

Final Notes

I do not recommend doing this in a multi-user environment as there is no guarantee that the user that copied to the clipboard will be the one who retrieves from it. Also, images/PDFs can be very large and the clipboard is slow.

I hope this is of some use to someone. It solved my problem, and saved me $900 by not having to buy a PDF Rasterizer control. Feel free to respond, and let me know if it helped you out or if you have any questions.

History

This article was posted first on the telerik forums.

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here

About the Author

Oleg Fridman

United States United States
No Biography provided

Comments and Discussions

 
Generalhelp me....................... Pinmemberlangamanish@yahoo.com22-Jul-08 19:14 
Generalthanks .. this code help me.. Pinmemberlangamanish@yahoo.com22-Jul-08 1:15 
GeneralReally Helpfull PinmemberKomal Bhatia16-Mar-08 20:57 
This topic helped me a lot while copying data to clipboard
 
Thanks A lot
 
Komal Bhatia

GeneralReally It help in the same case given by U PinmemberKKGaurav6-Nov-07 1:18 
QuestionHelp to tune the settings Pinmemberzan20063-Apr-07 5:44 
GeneralI've the same problem PinmemberUnfounds23-Jan-07 3:29 
GeneralRe: I've the same problem PinmemberOleg Fridman23-Jan-07 3:33 
GeneralRe: I've the same problem Pinmembershin99921-Jun-07 12:01 
GeneralNot work in Win2003 server with IIS6.0 PinmemberAjay Singh24-Oct-06 1:57 
AnswerRe: Not work in Win2003 server with IIS6.0 PinmemberOleg Fridman24-Oct-06 10:52 
AnswerRe: Not work in Win2003 server with IIS6.0 PinmemberOleg Fridman26-Oct-06 9:27 
GeneralRe: Not work in Win2003 server with IIS6.0 Pinmemberpatric4213-Nov-07 2:35 
GeneralRe: Not work in Win2003 server with IIS6.0 PinmemberOleg Fridman13-Nov-07 2:42 
GeneralWatch your EULA Pinmemberlrosenthol26-Sep-06 10:46 
GeneralRe: Watch your EULA PinmemberOleg Fridman26-Oct-06 9:30 
QuestionThis was right on the mark... Pinmemberwestberg25-Sep-06 11:25 
AnswerRe: This was right on the mark... PinmemberOleg Fridman25-Sep-06 14:54 

General General    News News    Suggestion Suggestion    Question Question    Bug Bug    Answer Answer    Joke Joke    Rant Rant    Admin Admin   

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.

| Advertise | Privacy | Mobile
Web01 | 2.8.140721.1 | Last Updated 20 Sep 2006
Article Copyright 2006 by Oleg Fridman
Everything else Copyright © CodeProject, 1999-2014
Terms of Service
Layout: fixed | fluid