117 行
无行尾
4.7 KiB
HTML
117 行
无行尾
4.7 KiB
HTML
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<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
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<title>Creating Ancillary Classes : CodeIgniter User Guide</title>
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<td><h1>CodeIgniter User Guide Version 2.0.1</h1></td>
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<a href="http://codeigniter.com/">CodeIgniter Home</a> ›
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<a href="../index.html">User Guide Home</a> ›
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Creating Ancillary Classes
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<h1>Creating Ancillary Classes</h1>
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<p>In some cases you may want to develop classes that exist apart from your controllers but have the ability to
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utilize all of CodeIgniter's resources. This is easily possible as you'll see.</p>
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<h2>get_instance()</h2>
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<p><strong>Any class that you instantiate within your controller functions can access CodeIgniter's native resources</strong> simply by using the <kbd>get_instance()</kbd> function.
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This function returns the main CodeIgniter object.</p>
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<p>Normally, to call any of the available CodeIgniter functions requires you to use the <kbd>$this</kbd> construct:</p>
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<code>
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<strong>$this</strong>->load->helper('url');<br />
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<strong>$this</strong>->load->library('session');<br />
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<strong>$this</strong>->config->item('base_url');<br />
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etc.
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</code>
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<p><kbd>$this</kbd>, however, only works within your controllers, your models, or your views.
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If you would like to use CodeIgniter's classes from within your own custom classes you can do so as follows:</p>
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<p>First, assign the CodeIgniter object to a variable:</p>
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<code>$CI =& get_instance();</code>
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<p>Once you've assigned the object to a variable, you'll use that variable <em>instead</em> of <kbd>$this</kbd>:</p>
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<code>
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$CI =& get_instance();<br /><br />
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$CI->load->helper('url');<br />
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$CI->load->library('session');<br />
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$CI->config->item('base_url');<br />
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etc.
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</code>
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<p class="important"><strong>Note:</strong> You'll notice that the above get_instance() function is being passed by reference:
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<br /><br />
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<var>$CI =& get_instance();</var>
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<br /><br />
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This is very important. Assigning by reference allows you to use the original CodeIgniter object rather than creating a copy of it.</p>
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<p>
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Previous Topic: <a href="creating_libraries.html">Creating Core Libraries</a>
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·
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<a href="#top">Top of Page</a> ·
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<a href="../index.html">User Guide Home</a> ·
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Next Topic: <a href="autoloader.html">Auto-loading Resources</a>
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</p>
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<p><a href="http://codeigniter.com">CodeIgniter</a> · Copyright © 2006 - 2011 · <a href="http://ellislab.com/">EllisLab, Inc.</a></p>
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