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| <td><h1>Code Igniter User Guide Version 1.4.0</h1></td> | |
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| Creating Ancillary Classes | |
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| <h1>Creating Ancillary Classes</h1> | |
| <p>In some cases you may want to develop classes that exist apart from your controllers but have the ability to | |
| utilize all of Code Igniter's resources. This is easily possible as you'll see.</p> | |
| <h2>get_instance()</h2> | |
| <p><strong>Any class that you instantiate within your controller functions can access Code Igniter's native resources</strong> simply by using the <kbd>get_instance()</kbd> function. | |
| This function returns the main Code Igniter object.</p> | |
| <p>Normally, to call any of the available Code Igniter functions requires you to use the <kbd>$this</kbd> construct:</p> | |
| <code> | |
| <strong>$this</strong>->load->helper('url');<br /> | |
| <strong>$this</strong>->load->library('session');<br /> | |
| <strong>$this</strong>->config->item('base_url');<br /> | |
| etc. | |
| </code> | |
| <p><kbd>$this</kbd>, however, only works within your controllers, your models, or your views. | |
| If you would like to use Code Igniter's classes from within your own custom classes you can do so as follows:</p> | |
| <p>First, assign the Code Igniter object to a variable:</p> | |
| <code>$obj =& get_instance();</code> | |
| <p>Once you've assigned the object to a variable, you'll use that variable <em>instead</em> of <kbd>$this</kbd>:</p> | |
| <code> | |
| $obj =& get_instance();<br /><br /> | |
| $obj->load->helper('url');<br /> | |
| $obj->load->library('session');<br /> | |
| $obj->config->item('base_url');<br /> | |
| etc. | |
| </code> | |
| <p class="important"><strong>Note:</strong> You'll notice that the above get_instance() function is being passed by reference: | |
| <br /><br /> | |
| <var>$obj =& get_instance();</var> | |
| <br /><br /> | |
| This is very important. Assigning by reference allows you to use the original Code Igniter object rather than creating a copy of it.</p> | |
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