$this

php.net

 1 <?php
 2 
 3 
 4 class A 
 5 {
 6     function foo()
 7     {
 8         if (isset($this)) {
 9             echo '$this is defined (',get_class($this),')'."\n";
10         } else {
11             echo '$this is not defined.'."\n";
12         }    
13     }
14 }
15 
16 class B 
17 {
18     function bar()
19     {
20         A::foo();
21     }
22 }
23 
24 $a = new A();
25 $a->foo();
26 
27 A::foo();
28 $b = new B();
29 $b->bar();
30 
31 B::bar();

$this is defined (A) 

( ! ) Strict standards: Non-static method A::foo() should not be called statically in D:\wamp64\www\w0827pm\w.php on line 27
Call Stack
#TimeMemoryFunctionLocation
1 0.0020 241448 {main}( ) ...\w.php:0

$this is not defined. 

( ! ) Deprecated: Non-static method A::foo() should not be called statically, assuming $this from incompatible context in D:\wamp64\www\w0827pm\w.php on line 20
Call Stack
#TimeMemoryFunctionLocation
1 0.0020 241448 {main}( ) ...\w.php:0
2 0.0030 242352 B->bar( ) ...\w.php:29

$this is defined (B) 

( ! ) Strict standards: Non-static method B::bar() should not be called statically in D:\wamp64\www\w0827pm\w.php on line 31
Call Stack
#TimeMemoryFunctionLocation
1 0.0020 241448 {main}( ) ...\w.php:0


( ! ) Strict standards: Non-static method A::foo() should not be called statically in D:\wamp64\www\w0827pm\w.php on line 20
Call Stack
#TimeMemoryFunctionLocation
1 0.0020 241448 {main}( ) ...\w.php:0
2 0.0030 242352 B::bar( ) ...\w.php:31

$this is not defined.

 

 

/*

The pseudo-variable $this is available when a    method is called from within an object    context. $this is a reference to the calling    object (usually the object to which the method belongs, but    possibly another object, if the method is called     statically from the context    of a secondary object).

  As of PHP 7.0.0 calling a non-static method statically from an incompatible  context results in $this being undefined inside the method. Calling a    non-static method statically from an incompatible context has been  deprecated as of PHP 5.6.0. As of PHP 7.0.0 calling a non-static method    statically has been generally deprecated (even if called from a compatible  context). Before PHP 5.6.0 such calls already triggered a strict notice.

*/

posted @ 2016-09-01 00:50  papering  阅读(200)  评论(0编辑  收藏  举报