I have this method that I want to use $this in but all I get is: Fatal error: Using $this when not in object context.
How can I get this to work?
public static function userNameAvailibility()
{
$result = $this->getsomthin();
}
This is the correct way
public static function userNameAvailibility()
{
$result = self::getsomthin();
}
Use self:: instead of $this-> for static methods.
See: PHP Static Methods Tutorial for more info :)
You can't use $this inside a static function, because static functions are independent of any instantiated object.
Try making the function not static.
Edit:
By definition, static methods can be called without any instantiated object, and thus there is no meaningful use of $this inside a static method.
Only static functions can be called within the static function using self:: if your class contains non static function which you want to use then you can declare the instance of the same class and use it.
<?php
class some_class{
function nonStatic() {
//..... Some code ....
}
Static function isStatic(){
$someClassObject = new some_class;
$someClassObject->nonStatic();
}
}
?>
The accessor this refers to the current instance of the class. As static methods does not run off the instance, using this is barred. So one need to call the method directly here. The static method can not access anything in the scope of the instance, but access everything in the class scope outside instance scope.
It's a pity PHP doesn't show a descriptive enough error. You can not use $this-> inside a static function, but rather use self:: if you have to call a function inside the same class
In the static method,properties are for the class, not the object.
This is why access to static methods or features is possible without creating an object.
$this refers to an object made of a class, but $self only refers to the same class.
Here is an example of what happens when a method of a class is called in a wrong way. You will see some warnings when execute this code but it will work and will print: "I'm A: printing B property". (Executed in php5.6)
class A {
public function aMethod() {
echo "I'm A: ";
echo "printing " . $this->property;
}
}
class B {
public $property = "B property";
public function bMethod() {
A::aMethod();
}
}
$b = new B();
$b->bMethod();
It seams that the variable $this, used in a method which is called as a static method, points to the instance of the "caller" class. In the example above there is $this->property used in the A class which points to a property of the B.
EDIT:
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).
PHP > The Basics
Related
I have this method that I want to use $this in but all I get is: Fatal error: Using $this when not in object context.
How can I get this to work?
public static function userNameAvailibility()
{
$result = $this->getsomthin();
}
This is the correct way
public static function userNameAvailibility()
{
$result = self::getsomthin();
}
Use self:: instead of $this-> for static methods.
See: PHP Static Methods Tutorial for more info :)
You can't use $this inside a static function, because static functions are independent of any instantiated object.
Try making the function not static.
Edit:
By definition, static methods can be called without any instantiated object, and thus there is no meaningful use of $this inside a static method.
Only static functions can be called within the static function using self:: if your class contains non static function which you want to use then you can declare the instance of the same class and use it.
<?php
class some_class{
function nonStatic() {
//..... Some code ....
}
Static function isStatic(){
$someClassObject = new some_class;
$someClassObject->nonStatic();
}
}
?>
The accessor this refers to the current instance of the class. As static methods does not run off the instance, using this is barred. So one need to call the method directly here. The static method can not access anything in the scope of the instance, but access everything in the class scope outside instance scope.
It's a pity PHP doesn't show a descriptive enough error. You can not use $this-> inside a static function, but rather use self:: if you have to call a function inside the same class
In the static method,properties are for the class, not the object.
This is why access to static methods or features is possible without creating an object.
$this refers to an object made of a class, but $self only refers to the same class.
Here is an example of what happens when a method of a class is called in a wrong way. You will see some warnings when execute this code but it will work and will print: "I'm A: printing B property". (Executed in php5.6)
class A {
public function aMethod() {
echo "I'm A: ";
echo "printing " . $this->property;
}
}
class B {
public $property = "B property";
public function bMethod() {
A::aMethod();
}
}
$b = new B();
$b->bMethod();
It seams that the variable $this, used in a method which is called as a static method, points to the instance of the "caller" class. In the example above there is $this->property used in the A class which points to a property of the B.
EDIT:
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).
PHP > The Basics
I've got a problem:
I'm writing a new WebApp without a Framework.
In my index.php I'm using: require_once('load.php');
And in load.php I'm using require_once('class.php'); to load my class.php.
In my class.php I've got this error:
Fatal error: Using $this when not in object context in class.php on line ... (in this example it would be 11)
An example how my class.php is written:
class foobar {
public $foo;
public function __construct() {
global $foo;
$this->foo = $foo;
}
public function foobarfunc() {
return $this->foo();
}
public function foo() {
return $this->foo;
}
}
In my index.php I'm loading maybe foobarfunc() like this:
foobar::foobarfunc();
but can also be
$foobar = new foobar;
$foobar->foobarfunc();
Why is the error coming?
In my index.php I'm loading maybe
foobarfunc() like this:
foobar::foobarfunc(); // Wrong, it is not static method
but can also be
$foobar = new foobar; // correct
$foobar->foobarfunc();
You can not invoke the method this way because it is not a static method.
foobar::foobarfunc();
You should instead use:
$foobar->foobarfunc();
If however, you have created a static method something like:
static $foo; // your top variable set as static
public static function foobarfunc() {
return self::$foo;
}
then you can use this:
foobar::foobarfunc();
You are calling a non-static method :
public function foobarfunc() {
return $this->foo();
}
Using a static-call :
foobar::foobarfunc();
When using a static-call, the function will be called (even if not declared as static), but, as there is no instance of an object, there is no $this.
So :
You should not use static calls for non-static methods
Your static methods (or statically-called methods) can't use $this, which normally points to the current instance of the class, as there is no class instance when you're using static-calls.
Here, the methods of your class are using the current instance of the class, as they need to access the $foo property of the class.
This means your methods need an instance of the class -- which means they cannot be static.
This means you shouldn't use static calls : you should instanciate the class, and use the object to call the methods, like you did in your last portion of code :
$foobar = new foobar();
$foobar->foobarfunc();
For more informations, don't hesitate to read, in the PHP manual :
The Classes and Objects section
And the Static Keyword page.
Also note that you probably don't need this line in your __construct method :
global $foo;
Using the global keyword will make the $foo variable, declared outside of all functions and classes, visibile from inside that method... And you probably don't have such a $foo variable.
To access the $foo class-property, you only need to use $this->foo, like you did.
If you are invoking foobarfunc with resolution scope operator (::), then you are calling it statically, e.g. on the class level instead of the instance level, thus you are using $this when not in object context. $this does not exist in class context.
If you enable E_STRICT, PHP will raise a Notice about this:
Strict Standards:
Non-static method foobar::foobarfunc() should not be called statically
Do this instead
$fb = new foobar;
echo $fb->foobarfunc();
On a sidenote, I suggest not to use global inside your classes. If you need something from outside inside your class, pass it through the constructor. This is called Dependency Injection and it will make your code much more maintainable and less dependant on outside things.
First you understand one thing, $this inside a class denotes the current object.
That is which is you are created out side of the class to call class function or variable.
So when you are calling your class function like foobar::foobarfunc(), object is not created.
But inside that function you written return $this->foo(). Now here $this is nothing. Thats why its saying Using $this when not in object context in class.php
Solutions:
Create a object and call foobarfunc().
Call foo() using class name inside the foobarfunc().
When you call the function in a static context, $this simply doesn't exist.
You would have to use this::xyz() instead.
To find out what context you're in when a function can be called both statically and in an object instance, a good approach is outlined in this question: How to tell whether I’m static or an object?
Fast method : (new foobar())->foobarfunc();
You need to load your class replace :
foobar::foobarfunc();
by :
(new foobar())->foobarfunc();
or :
$Foobar = new foobar();
$Foobar->foobarfunc();
Or make static function to use foobar::.
class foobar {
//...
static function foobarfunc() {
return $this->foo();
}
}
It seems to me to be a bug in PHP.
The error
'Fatal error: Uncaught Error: Using $this when not in object context
in'
appears in the function using $this, but the error is that the calling function is using non-static function as a static. I.e:
Class_Name
{
function foo()
{
$this->do_something(); // The error appears there.
}
function do_something()
{
///
}
}
While the error is here:
Class_Name::foo();
$foobar = new foobar; put the class foobar in $foobar, not the object. To get the object, you need to add parenthesis: $foobar = new foobar();
Your error is simply that you call a method on a class, so there is no $this since $this only exists in objects.
Just use the Class method using this foobar->foobarfunc();
I've got a problem:
I'm writing a new WebApp without a Framework.
In my index.php I'm using: require_once('load.php');
And in load.php I'm using require_once('class.php'); to load my class.php.
In my class.php I've got this error:
Fatal error: Using $this when not in object context in class.php on line ... (in this example it would be 11)
An example how my class.php is written:
class foobar {
public $foo;
public function __construct() {
global $foo;
$this->foo = $foo;
}
public function foobarfunc() {
return $this->foo();
}
public function foo() {
return $this->foo;
}
}
In my index.php I'm loading maybe foobarfunc() like this:
foobar::foobarfunc();
but can also be
$foobar = new foobar;
$foobar->foobarfunc();
Why is the error coming?
In my index.php I'm loading maybe
foobarfunc() like this:
foobar::foobarfunc(); // Wrong, it is not static method
but can also be
$foobar = new foobar; // correct
$foobar->foobarfunc();
You can not invoke the method this way because it is not a static method.
foobar::foobarfunc();
You should instead use:
$foobar->foobarfunc();
If however, you have created a static method something like:
static $foo; // your top variable set as static
public static function foobarfunc() {
return self::$foo;
}
then you can use this:
foobar::foobarfunc();
You are calling a non-static method :
public function foobarfunc() {
return $this->foo();
}
Using a static-call :
foobar::foobarfunc();
When using a static-call, the function will be called (even if not declared as static), but, as there is no instance of an object, there is no $this.
So :
You should not use static calls for non-static methods
Your static methods (or statically-called methods) can't use $this, which normally points to the current instance of the class, as there is no class instance when you're using static-calls.
Here, the methods of your class are using the current instance of the class, as they need to access the $foo property of the class.
This means your methods need an instance of the class -- which means they cannot be static.
This means you shouldn't use static calls : you should instanciate the class, and use the object to call the methods, like you did in your last portion of code :
$foobar = new foobar();
$foobar->foobarfunc();
For more informations, don't hesitate to read, in the PHP manual :
The Classes and Objects section
And the Static Keyword page.
Also note that you probably don't need this line in your __construct method :
global $foo;
Using the global keyword will make the $foo variable, declared outside of all functions and classes, visibile from inside that method... And you probably don't have such a $foo variable.
To access the $foo class-property, you only need to use $this->foo, like you did.
If you are invoking foobarfunc with resolution scope operator (::), then you are calling it statically, e.g. on the class level instead of the instance level, thus you are using $this when not in object context. $this does not exist in class context.
If you enable E_STRICT, PHP will raise a Notice about this:
Strict Standards:
Non-static method foobar::foobarfunc() should not be called statically
Do this instead
$fb = new foobar;
echo $fb->foobarfunc();
On a sidenote, I suggest not to use global inside your classes. If you need something from outside inside your class, pass it through the constructor. This is called Dependency Injection and it will make your code much more maintainable and less dependant on outside things.
First you understand one thing, $this inside a class denotes the current object.
That is which is you are created out side of the class to call class function or variable.
So when you are calling your class function like foobar::foobarfunc(), object is not created.
But inside that function you written return $this->foo(). Now here $this is nothing. Thats why its saying Using $this when not in object context in class.php
Solutions:
Create a object and call foobarfunc().
Call foo() using class name inside the foobarfunc().
When you call the function in a static context, $this simply doesn't exist.
You would have to use this::xyz() instead.
To find out what context you're in when a function can be called both statically and in an object instance, a good approach is outlined in this question: How to tell whether I’m static or an object?
Fast method : (new foobar())->foobarfunc();
You need to load your class replace :
foobar::foobarfunc();
by :
(new foobar())->foobarfunc();
or :
$Foobar = new foobar();
$Foobar->foobarfunc();
Or make static function to use foobar::.
class foobar {
//...
static function foobarfunc() {
return $this->foo();
}
}
It seems to me to be a bug in PHP.
The error
'Fatal error: Uncaught Error: Using $this when not in object context
in'
appears in the function using $this, but the error is that the calling function is using non-static function as a static. I.e:
Class_Name
{
function foo()
{
$this->do_something(); // The error appears there.
}
function do_something()
{
///
}
}
While the error is here:
Class_Name::foo();
$foobar = new foobar; put the class foobar in $foobar, not the object. To get the object, you need to add parenthesis: $foobar = new foobar();
Your error is simply that you call a method on a class, so there is no $this since $this only exists in objects.
Just use the Class method using this foobar->foobarfunc();
I have this method that I want to use $this in but all I get is: Fatal error: Using $this when not in object context.
How can I get this to work?
public static function userNameAvailibility()
{
$result = $this->getsomthin();
}
This is the correct way
public static function userNameAvailibility()
{
$result = self::getsomthin();
}
Use self:: instead of $this-> for static methods.
See: PHP Static Methods Tutorial for more info :)
You can't use $this inside a static function, because static functions are independent of any instantiated object.
Try making the function not static.
Edit:
By definition, static methods can be called without any instantiated object, and thus there is no meaningful use of $this inside a static method.
Only static functions can be called within the static function using self:: if your class contains non static function which you want to use then you can declare the instance of the same class and use it.
<?php
class some_class{
function nonStatic() {
//..... Some code ....
}
Static function isStatic(){
$someClassObject = new some_class;
$someClassObject->nonStatic();
}
}
?>
The accessor this refers to the current instance of the class. As static methods does not run off the instance, using this is barred. So one need to call the method directly here. The static method can not access anything in the scope of the instance, but access everything in the class scope outside instance scope.
It's a pity PHP doesn't show a descriptive enough error. You can not use $this-> inside a static function, but rather use self:: if you have to call a function inside the same class
In the static method,properties are for the class, not the object.
This is why access to static methods or features is possible without creating an object.
$this refers to an object made of a class, but $self only refers to the same class.
Here is an example of what happens when a method of a class is called in a wrong way. You will see some warnings when execute this code but it will work and will print: "I'm A: printing B property". (Executed in php5.6)
class A {
public function aMethod() {
echo "I'm A: ";
echo "printing " . $this->property;
}
}
class B {
public $property = "B property";
public function bMethod() {
A::aMethod();
}
}
$b = new B();
$b->bMethod();
It seams that the variable $this, used in a method which is called as a static method, points to the instance of the "caller" class. In the example above there is $this->property used in the A class which points to a property of the B.
EDIT:
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).
PHP > The Basics
I am debugging a site
I am having to work with classes which I am not that used to as of yet.
There is this class in this site that processes a $this but there does not seem to be any variable passed to the class.
the class is like this
class myclass extends otherclass{
function dosmthtomyclass{
print_r($this);
}
}
function dosmttomyclass prints an array.
there are bunch of variables defined protected in the class but there does not seem to be any specific value specified for any of those variables and there is no constructor in the class to the pass the value to.
I am seriously confused as to where the variable must have been passed from.
This may be something really basic but any help would be appreciated.
what are the possible ways of passing variables to the class
$this refers to the current object. according to PHP documentation
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).
here is some detailed explanation about it. which may help you to understand
What does the variable $this mean in PHP?
this is because myclass is getting the data from otherClass... like this:
<?php
class otherclass{
public $name="Mike";
}
class myclass extends otherclass {
function dosmthtomyclass() {
print_r($this);
}
}
$test=new myclass();
$test->dosmthtomyclass(); //prints "[name] => Mike"
You need to go through the manual and/or tutorials on OOP. Because this is the only way you'll understand OOP. Start with this: http://www.php.net/manual/en/language.oop5.basic.php
$this refers to the current instance of the object. Read about PHP+visibility to understand why private varianbles/methods aren't visisble to child classes (extended classes).
Good luck!
$this refers to the current object of the class. Execute the following code for more clarity:
<?php
class abc {
var $val = 3;
function show()
{
print_r($this);
}
}
$ob = new abc();
$ob->show();
Maybe some background on using classes in php can help you:
$this is used to refer to the hierarchy within the class.
E.g., you could have a class like this:
class Phpclass{
public function main(){
echo "public function called<br/>";
$this->helloworld();
}
private function helloworld(){
echo "hello world";
}
}
$phpclass=new Phpclass();
$phpclass->main();
This class is a blueprint of an object that will be instantiated with the variables $phpclass. As main() is a plublic function in the class, it can be called from outside the class. The private function can only be called from inside the class, so the main() function uses $this as identifier for the class itself to call the private function helloworld() inside itself. Without $this, the object wouldn't know that you are referring to a function inside itself.
First, the above will echo out "public function called", then "hello world".