pdf to image c# free : Create a pdf form to fill out SDK application service wpf html windows dnn 121a0d02665536dcf08e9ac3b422d11818-part268

162
Elements ofObject-orientedDesign
The clear advantage of the MVC pattern is its clear-cut approach to separating
each domain of an application into a separate container. This, inturn, makes your
applications easier to maintain and to extend, particularly because you can easily
modularize each element, minimizing thepossibility ofcode duplication.
TheActiveRecord Pattern
The last patternthat we will examine isthe ActiveRecord pattern. This is used to en-
capsulate access to a data source so that the act ofaccessing its components—both
for reading and for writing—is, in fact, hidden withinthe class that implements the
pattern,allowingitscallerstoworryaboutusing thedata,as opposedtodealing with
the database.
The concept behind ActiveRecord is, therefore, quite simple, but its implemen-
tation can be very complicated, depending on the level of functionality that a class
based on this pattern is to provide. This is usually caused by the fact that, while de-
velopers tend to deal with individual database fields individually and interactively,
SQLdealswiththemaspartofrows thatmustbewrittenback tothedatabase atomi-
cally. Inaddition,thesynchronizationofdatawithinyour scripttothedatainsidethe
database can bevery challenging,because the data maychange after you’ve fetched
it fromthe databasewithout giving your code any notice.
The Standard PHP Library
The Standard PHP Library (SPL) is a great addition to PHP 5. It provides a number
of very useful facilities that expose some of PHP’s internal functionality and allow
the “userland” developer to write objects that are capable of behaving like arrays,
or thattransparently implementcertainiterative design patterns to PHP’s own core
functionality, sothat you, for example, use a
foreach()
construct to loop through an
object as if it were an array, or even access its individual elements using the array
operator
[]
.
SPL works primarily by providing a number of interfaces that can be used to im-
plement the functionality required to performcertain operations. By far, the largest
number ofpatterns exposed bySPLare iterators; they allow, among other things:
• ArrayAccess to objects
Create a pdf form to fill out - C# PDF Field Edit Library: insert, delete, update pdf form field in C#.net, ASP.NET, MVC, Ajax, WPF
Online C# Tutorial to Insert, Delete and Update Fields in PDF Document
adding form fields to pdf; change font size in pdf form field
Create a pdf form to fill out - VB.NET PDF Field Edit library: insert, delete, update pdf form field in vb.net, ASP.NET, MVC, Ajax, WPF
How to Insert, Delete and Update Fields in PDF Document with VB.NET Demo Code
edit pdf form; adding image to pdf form
ElementsofObject-orientedDesign
163
• Simple Iteration
• Seekable Iteration
• Recursive Iteration
• Filtered Iteration
Accessing Objects as Arrays
The
ArrayAccess
interface canbe used to provide a means for your object to expose
themselves aspseudo-arrays to PHP:
interface ArrayAccess {
function offsetSet($offset, $value);
function offsetGet($offset);
function offsetUnset($offset);
function offsetExists($offset);
}
This interface provides the basic methods required by PHP to interact with anarray:
offsetSet()
sets a value inthe array
offsetGet()
retrieves a value fromthe array
offsetUnset()
removesa value fromthe array
offsetExists()
determines whether anelement exists
As avery quick example,consider the following class, which“emulates” anarray that
onlyaccepts elements with numeric keys:
class myArray implements ArrayAccess {
protected $array = array();
function offsetSet ($offset, $value) {
if (!is
_
numeric ($offset)) {
throw new Exception ("Invalid key $offset");
}
C# PDF Form Data fill-in Library: auto fill-in PDF form data in C#
Able to fill out all PDF form field in C#.NET. RasterEdge XDoc.PDF SDK package provides PDF field processing features for your C# project.
chrome pdf save form data; pdf form change font size
VB.NET PDF- View PDF Online with VB.NET HTML5 PDF Viewer
Bookmark: Edit Bookmark. Metadata: Edit, Delete Metadata. Form Process. Annotate PDF in WPF, C#.NET PDF Create, C#.NET Users can view PDF document in single page
create a fillable pdf form; adding an image to a pdf form
164
Elements ofObject-orientedDesign
$this->array[$offset] = $value;
}
function offsetGet ($offset) {
return $this->array[$offset];
}
function offsetUnset ($offset) {
unset ($this->array[$offset]);
}
function offsetExists ($offset) {
return array
_
key
_
exists ($this->array, $offset);
}
}
$obj = new myArray();
$obj[1] = 2;
// Works.
$obj[’a’] = 1;
// Throws exception.
As you can see, this feature of SPL provides you with an enormous amount of con-
trol over one of PHP’s most powerful (and most useful) data types. Used properly,
ArrayAccess
is a great tool for building applications that encapsulate complex be-
haviours ina data type that everyone is used to.
SimpleIteration
The
Iterator
interface is the simplest of the iterator family, providing simple itera-
tionover any single-dimensionarray. Itlooks like this:
interface Iterator {}
function current();
function next();
function rewind();
function key();
function valid();
function seek($key);
}
You can see a simple implementation of the interface that allows iteration over a
private property containing a simple array:
C# HTML5 PDF Viewer SDK to view PDF document online in C#.NET
Form Process. Data: Read, Extract Field Data. Data: Auto Fill Barcode Read. Barcode Create. OCR. Twain. View PDF Online. Users can view PDF document in single page
acrobat create pdf form; pdf fillable form creator
VB.NET PDF - View PDF with WPF PDF Viewer for VB.NET
Bookmark: Edit Bookmark. Metadata: Edit, Delete Metadata. Form Process. Annotate PDF in WPF, C#.NET PDF Create, C#.NET rotate one PDF page or whole PDF while in
add text field to pdf acrobat; change tab order in pdf form
ElementsofObject-orientedDesign
165
class myData implements iterator {
private $
_
myData = array(
"foo",
"bar",
"baz",
"bat");
private $
_
current = 0;
function current() {
return $this->myData[$this->current];
}
function next() {
$this->current += 1;
}
function rewind() {
$this->current = 0;
}
function key() {
return $this->current;
}
function valid() {
return isset($this->myData[$this->current]);
}
}
$data = new myData();
foreach ($data as $key => $value) {
echo "$key: $value\n";
}
Thisexamplewilliterateover each ofthefourelementsinthe
myData
privateproperty
intheexact same way
foreach()
works ona standard Array.
Seekable Iterators
The next step up from a standard Iterator is the
SeekableIterator
,which extends
the standard
Iterator
interface and adds a
seek()
method to enable the ability to
retrieve a specific item frominternal data store. Its interface lookslike this:
C# WPF PDF Viewer SDK to view PDF document in C#.NET
Form Process. Data: Read, Extract Field Data. Data: Auto Fill-in NET Annotate PDF in WPF, C#.NET PDF Create, C#.NET to rotate one PDF page or whole PDF while in
change font size in pdf fillable form; add attachment to pdf form
C#: XDoc.HTML5 Viewer for .NET Online Help Manual
Click to open edited file in web browser in PDF form which can be printed Click it and click on the document to create a current date Office 2003 and 2007, PDF.
convert word to editable pdf form; adding images to pdf forms
166
Elements ofObject-orientedDesign
interface SeekableIterator {
function current();
function next();
function rewind();
function key();
function valid();
function seek($index);
}
Recursive Iteration
Recursive Iterationallows looping over multi-dimensional tree-like data structures.
SimpleXML, for example, uses recursive iteration to allow looping through complex
XML document trees.
Tounderstand howthis works,consider the following complex array:
$company = array(
array("Acme Anvil Co."),
array(
array(
"Human Resources",
array(
"Tom",
"Dick",
"Harry"
)
),
array(
"Accounting",
array(
"Zoe",
"Duncan",
"Jack",
"Jane"
)
)
)
);
Our goalis toprint out something like this:
.NET PDF Document Viewing, Annotation, Conversion & Processing
Add, Update, Delete form fields programmatically. Allow to create digital signature. Online Demo See the PDF SDK for .NET in action and check how much they can
best pdf form creator; change font in pdf form field
VB.NET PDF Text Extract Library: extract text content from PDF
Extract highlighted text out of PDF document. Enable extracting PDF text to another PDF file, and other formats such as TXT and SVG form.
add form fields to pdf; adding text fields to pdf acrobat
ElementsofObject-orientedDesign
167
<h1>Company: Acme Anvil Co.</h1>
<h2>Department: Human Resources</h2>
<ul>
<li>Tom</li>
<li>Dick</li>
<li>Harry</li>
</ul>
<h2>Department: Accounting</h2>
<ul>
<li>Zoe</li>
<li>Duncan</li>
<li>Jack</li>
<li>Jane</li>
</ul>
By extending
RecursiveIteratorIterator
,we can define the
beginChildren()
and
endChildren()
methods so that our class can output the start and end <
ul
>tags
withoutany of the complexities normally associated with recursion(such as, for ex-
ample, keeping track of multiple nested levels of nesting). The example shown be-
low defines two classes, our custom
RecursiveIteratorIterator
and a very simple
RecursiveArrayObject
:
class Company
_
Iterator extends RecursiveIteratorIterator {
function beginChildren()
{
if ($this->getDepth() >= 3) {
echo str
_
repeat("\t", $this->getDepth() - 1);
echo "<ul>" . PHP
_
EOL;
}
}
function endChildren()
{
if ($this->getDepth() >= 3) {
echo str
_
repeat("\t", $this->getDepth() - 1);
echo "</ul>" . PHP
_
EOL;
}
}
}
class RecursiveArrayObject extends ArrayObject {
function getIterator() {
return new RecursiveArrayIterator($this);
VB.NET PDF- HTML5 PDF Viewer for VB.NET Project
Bookmark: Edit Bookmark. Metadata: Edit, Delete Metadata. Form Process. Read, Extract Field Data. Data: Auto Fill-in Field Create PDF Online in HTML5 PDF Viewer.
add fillable fields to pdf online; change font size pdf fillable form
VB.NET PDF - WPF PDF Viewer for VB.NET Program
Bookmark: Edit Bookmark. Metadata: Edit, Delete Metadata. Form Process. Annotate PDF in WPF, C#.NET PDF Create, C#.NET Users can rotate PDF pages, zoom in or zoom
chrome save pdf with fields; pdf form save in reader
168
Elements ofObject-orientedDesign
}
}
Then, to produce our desired end result, we simply use this code:
$it = new Company
_
Iterator(new RecursiveArrayObject($company));
$in
_
list = false;
foreach ($it as $item) {
echo str
_
repeat("\t", $it->getDepth());
switch ($it->getDepth()) {
case 1:
echo "<h1>Company: $item</h1>" . PHP
_
EOL;
break;
case 2:
echo "<h2>Department: $item</h2>" . PHP
_
EOL;
break;
default:
echo "<li>$item</li>" . PHP
_
EOL;
}
}
FilteringIterators
The
FilterIterator
class can be used to filter the items returned by aniteration:
class NumberFilter extends FilterIterator
{
const FILTER
_
EVEN = 1;
const FILTER
_
ODD = 2;
private $
_
type;
function
__
construct($iterator, $odd
_
or
_
even = self::FILTER
_
EVEN)
{
$this->
_
type = $odd
_
or
_
even;
parent::
__
construct($iterator);
}
function accept()
{
if ($this->
_
type == self::FILTER
_
EVEN) {
return ($this->current() % 2 == 0);
ElementsofObject-orientedDesign
169
} else {
return ($this->current() % 2 == 1);
}
}
}
$numbers = new ArrayObject(range(0, 10));
$numbers
_
it = new ArrayIterator($numbers);
$it = new NumberFilter($numbers
_
it, NumberFilter::FILTER
_
ODD);
foreach ($it as $number) {
echo $number . PHP
_
EOL;
}
The
accept()
method simply determines whether any given element should be al-
lowed inthe iteration;note that
FilterIterator
alreadyimplementsall ofthe meth-
ods of
ArrayAccess
,sothat,effectively,from the outsideour classcanstill be used as
anarray.
This example outputs only the odd numbers stored in the array:
1
3
5
7
9
Summary
Object Oriented programming,coupled with DesignPatterns—includingthose pro-
vided by SPL—is the key tore-usable and highly modular code.
The more forethought you give your design, the more likely you are to be able to
re-use at least some of it, later, saving time and effort in the future—not to mention
that proper designtechniques also make code easier to maintainand extend.
Bringing thisexperience to the tableis whatmakes you truly versatile;as we men-
tioned, designpatterns are,after all,largelylanguage- and problem-independent.
Chapter 9
XML and Web Services
ExtensibleMarkup Language (XML) has becomethe formatofchoice for communi-
cation between disparate systems. Possibly its most common applications are the
popular Really Simple Syndication (RSS) and Atom feed formats embraced by the
blogging community for contentsyndication. However, XML is successfully used in
many more instancesto store arbitrary data in a well-structured way.
Closely linked toXML,Web services havegivenrise toa newwayofthinking about
data. Web services provide a way by which any computer may exchange data with
another using the web as a transport medium. Some Web services are free—indeed
some companies are using free Web services as a convenient way to allowthird par-
ties toextend their products and enrich their business models—while others charge
fortheir usage;some arecomplex,othersaresimple. Regardless,onething iscertain:
Web services arechanging the landscape of the Web.
One of the most significant changes made inPHP 5 is the way inwhich PHP han-
dles XMLdata. Theunderlyingcode inthePHPenginewas transformed andrearchi-
tected toprovidea seamlessset ofXML parsing tools that work together and comply
with World Wide Web Consortium (W3C) recommendations. Whereas PHP 4 used
adifferent code library to implement each XML tool, PHP 5 takes advantage of a
standardizedsingle library: theGnomeXML library(
libxml2
). Inaddition,PHP5 in-
troduces many newtools to make the task ofworking with XMLdocuments simpler
and easier.
Documents you may be interested
Documents you may be interested