Adobe FDF Tookit With C# / .NET

If you're providing users a PDF that requires them to type in or hand write information that you already have (ie. in a database), why not provide a PDF that has been dynamically pre-populated with this information instead?

Here's how to accomplish this using Adobe's FDF Toolkit and C# as I wasn't able to find a good source on how to build a similar app in C# when I was once in need. This guide assumes you have some familiarity working with .NET, C#, Acrobat, FDF (Form Data Form), and PDF.

Create your PDF using Adobe Acrobat

1. Open an existing PDF or create a new file
2. Create a text field
3. Name it: fooField
4. Save your PDF as myfile.pdf

Setup FDF Toolkit

1. Download FDF Toolkit from Adobe Developer Center
2. Copy the files fdfacx.dll and fdftk.dll to a folder on your web server, either a global folder or even your application's /bin folder.
3. From the Windows Command Prompt, type: regsvr32 c:\path\to\file\fdfacx.dll where path\to\file is the actual path to the file.
4. Use the Type Library Importer included with Visual Studio to create a CLR assembly. At the Command Prompt, type: tlbimp FdfAcX.dll /out:fdfacx_clr.dll (modify paths as necessary).
5. Place the newly created CLR assembly fdfacx_clr.dll in your .NET application's /bin folder.

C# Source Code

using fdfacx_clr; // include generated CLR assembly

private string foo;
foo = "bar";

FdfAppClass FdfAcX_App = new FdfAppClass();
FdfDoc outputFDF = (FdfDoc)FdfAcX_App.FDFCreate();

outputFDF.FDFSetFile("http://path/to/pdf/myfile.pdf"); // absolute web path to your pdf file
outputFDF.FDFSetValue("fooField", foo, false);
outputFDF.FDFSetStatus(foo + " will now be inserted into fooField");

Response.ContentType = "application/vnd.fdf";
Response.Write(outputFDF.FDFSaveToStr());
Response.End();
outputFDF.FDFClose();

That's it. Fire up your C# ASP.Net web application and navigate to your start page and it should create a FDF on the fly that will point to your PDF.

Forgive me if I've left anything out or made any errors as it's been awhile since I actually worked on the project. Leave a comment if you run into any problems!