The Write method, after the bytes are written to the specified path, invokes the Read method to return the bytes just written. I concede that this is a bit inefficient because why should I have to read to get the bytes I just provided? That's a fair critique. Like making the one method private, this too was an arbitrary design decision I made.
The idea is that if I get bytes back, the calling program can presume the bytes were written in the first place. Could the method return a Boolean instead?
Of course it could, and if you want that behavior, you're free to change the code as you see fit. Now that you can create and read PDF files, the next and final step is to read and write field values from and to those PDF files.
Listing 5 illustrates the code to accomplish the first task, to get field data. The one thing to take note of is that in all cases, the value retrieved is a string. Once a field value is rendered on a PDF, it's a string and often, it's a formatted string, as would be the case for phone numbers, dates, and social security numbers, to name three examples.
A PdfField array where each element contains the field name, the value, and the formatted value. Listing 7 illustrates the PdfField Class. Why doesn't the SetData method use the getFormFields method? The getFormFields method closes the PdfDocument instance. Accordingly, while you strive for maximum re-use, practicality often dictates that you sometimes need to put that ideal on the shelf.
Why is the field value in this context always a string. It has to do with the context in which the data is being used. When you render data in a report, the fact that the underlying value is a date, integer, or Boolean type isn't important. When you deal with and manipulate data in code, its underlying data type matters. Integers are a great example. In code, an integer value will be The PDFLibrary simply takes that information and applies it. From a separation of concerns standpoint, the PDFLibrary isn't concerned with how or why a given piece of data is an integer or a date or why it's displayed in a certain way.
Rather, the PDFLibrary takes the data as it finds it. The PDFLibrary is stateless. It accepts arguments immutable arguments, to be precise , acts on those arguments, and provides an immutable response. The PDFLibrary is inherently thread safe. Therefore, there's nothing to be gained from creating an PDFLibrary instance variable. If you don't need to create state, don't. If you don't need a variable, don't create one. The same goes for always implementing a Using statement when the underlying class implements the IDisposable interface.
The best place to start is with the unit tests. In the Web application, I'll cover how to create an abstraction to the PDFLibrary that's better suited to meet the Web application's needs.
My Subscriber Account Advertise Write. Training Home State of. Staffing Home Looking for Staff? Looking for Work? Contact Us. Dark Kimbie. Published in:. Filed under: iText PDFs. The provision I want to draw your attention to is the final paragraph: You can be released from the requirements of the license [AGPL] by purchasing a commercial license. Write field data to a PDF byte array. Additional functions include: Determining whether a given file is a PDF.
Retrieving a field name list from a PDF. Figure 2: HelloWorld. There are several problems with the code. First, although the text mentions that streams can be used to create files, nowhere is that technique demonstrated. Instead, they just show a figure with a rendered PDF, notwithstanding the fact that the helloworld.
Second, in the real world, not all layers in your application architecture have knowledge of or can use a file path. This is especially true if you're using loosely coupled services as you should be using. In the real world, you need to deal with byte arrays and streams to read from and write to components that, in turn, will eventually write that data to some source, whether it's a disk or another service.
That necessarily means that when you use such things, you must wrap their usage in a Using statement. To not do so ends up leading to the real and likely possibility of memory leaks. Note on the Immutable Classes Throughout the code in this article, you'll see numerous references to immutable classes. Listing 2. GetAcroForm doc, false. Add x. Key, x. Value ; return builder. PDF documents that do not contain controls; those meant to be printed and filled in with a pencil, cannot be completed using this approach.
Further, though not demonstrated here, one can also use iTextSharp to create a PDF document with embedded controls. The solution consists of a single Win Forms project with a single form. All of the project code is contained with the single Windows form. The form itself contains only a docked textbox used to display all of the field names from an existing PDF document.
The completed PDF is generated and stored in the local file system; the PDF is not opened for display by the application. The template PDF itself is never populated and it is used only to define the format and contents of the completed PDF. Figure 2: Solution Explorer. As was previously mentioned, all of the code used in the demonstration application is contained entirely in the project's single Windows form.
The following section will describe the contents of the code file. The file begins with the appropriate library imports needed to support the code. Note that the iTextSharp libraries have been included into the project. The namespace and class declaration are in the default configuration. The next section of code contains the default constructor and the form 1 load event handler. During form load, two functions are called; those functions are used to display all of the fields present in the template PDF and to create a new PDF populated with a set of field values.
Checkbox controls may be a little more challenging to figure out. I tried passing several values to the checkbox controls before lining up a winner. In this example, I tried pass zero, one, true, false, etc. Add a comment. Active Oldest Votes. Dynamic XFA As you seem to be new to iText, it is assumed that you'll use the latest version of iText which is iText 7 as opposed to a version that is being phased out iText 5 or obsolete all versions prior to iText 2.
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