Invoke function from initiated class within a class

[eros]

[PHP]
<?php
//clsrecordset.ph p
class Recordset extends Database{

public function Recordset( ) { }

public function query( ) { }

public function endOfFile ( ) { }

}
?>[/PHP]

[PHP]<?php
//clssearchindex. php
require_once('c lsrecordset.php ');

class Searchindex {
private c_rs;

public function Searchindex ( ) {
$this->c_rs = new Recordset( );
}

public function getSQL ( ) { }

public function getData ( ) {
$rs = $this->c_rs->query($this->getSQL()); // error occurred this line
$this->c_rs->query($this->getSQL());
if ( $this->c_rs->endOfFile() ) {
$norecs = true;
}
}
}
?>[/PHP]

Error message: Call to a member function query() on a non-object

Additional, when I type the $this->c_rs-> , there is no intellisense on this case that's why I know there is something wrong and couldn't find the function.

Help: How can I call the function from the initiated class in order to use in other class?

[Atli]

Are you sure you have called the method that initializes the c_rs object?

You should consider adding a constructor to initialize it, then there will be no risk of the variable not being initialized.

[eros]

Are you sure you have called the method that initializes the c_rs object?

You should consider adding a constructor to initialize it, then there will be no risk of the variable not being initialized.

[PHP]<?php
$pg = new Searchindex ( );
$pg->getData ( );
?>[/PHP]

Yes Sir, I use the new operator during initiation of the class then it is automatically invoke the Searchindex　con structor.

[Atli]

[PHP]<?php
$pg = new Searchindex ( );
$pg->getData ( );
?>[/PHP]

Yes Sir, I use the new operator during initiation of the class then it is automatically invoke the Searchindex　con structor.

Yea sorry, totally overlooked that. I've gotten to used to the __construct() syntax :)

The error is where you create the c_rs variable, you forgot the $ before the variable name.

[eros]

Yea sorry, totally overlooked that. I've gotten to used to the __construct() syntax :)

The error is where you create the c_rs variable, you forgot the $ before the variable name.

I think it is documented in php documentation when accessing the members itself, you only need the member name before $this-> .

For example:
[PHP]<?php
class MyClass {
private var1;
public var2;

public function MyClass ( ) {
// variable members initialization
$this->var1 = 1;
$this->var2 = "variable2" ;
// also calling function members
$this->MyFunction ( );

// "$" should be use when you need local variable.
// Therefore, $this->var? and $var? are treated differently.
$var1 = 2;
$var2 = "variable2" ;

$result = $this->var1 + $var1; // output 3
}

public function MyFunction ( ) { }
}
?>[/PHP]

[eros]

The above are the basics of PHP OOP, therefore it is not questionable unless I overlooked the code after my several times of investigations of what is really happening.

I created this topic because I feel strange of the error.. It must be correct syntactically and logically....

[eros]

Invoke function from initiated class within a class [CLOSED]

I am very sorry guys I just missed looked / overlooked the code.

The code posted here was different in my source code.

[PHP]<?php
class Searchindex ( ) {
private $c_rs;

public function Searchindex ( ) {
/* this is the problem.
* It should be $this->c_rs = new Recordset ( );
*/
$c_rs = new Recordset ( );
}
}
?>[/PHP]

I make my own headache ;).. Thanks guys.

TOPIC CLOSED

[Atli]

Glad your code is working now.

Just to clear things up tho, take a look at this:
[code=php]
class myclass
{
// This is incorrect, and will cause errors!
private myVar;

// This is correct
private $myvar;

function testFunc() {
// This is correct, and will always refer to the variable
// we declared before the function.
echo $this->myvar;

# EDIT, got this wrong the first time. It has been corrected.
// This is not valid, it appears that the class variable
// $myvar does not exist inside the scope of this function.
// This will cause PHP to print a warning, if warnings are enabled.
echo $myvar;
}
}
[/code]

[eros]

Glad your code is working now.

Just to clear things up tho, take a look at this:
[code=php]
class myclass
{
// This is incorrect, and will cause errors!
private myVar;

// This is correct
private $myvar;

function testFunc() {
// This is correct, and will always refer to the variable
// we declared before the function.
echo $this->myvar;

// This is also correct, because the myvar variable
// is declared inside the class, but any instances of
// of $myvar inside the function will take over the scope.
echo $myvar;
}
}
[/code]

Do you mean $this->myvar and $myvar are the same memory location? It means changes in $myvar are automatically reflected in $this->myvar and viceversa?

[Atli]

Do you mean $this->myvar and $myvar are the same memory location? It means changes in $myvar are automatically reflected in $this->myvar and viceversa?

No, it doesn't appear to work like that. I thought it did tho :/
Which means my earlier post was wrong. (I've edited it btw to show the error)

I made a simple test:
[code=php]
class myclass
{
private $myvar;

function myfunc()
{
$this->myvar = 5;

echo $myvar; // = 'Undefined wariable' warning.
echo $this->myvar; // = 5

$myvar = 10;

echo $myvar; // = 10
echo $this->myvar; // = 5
}
}
[/code]

So based on that, class variables can not be used inside class methods without $this.

It is possible, however, that this behavior may vary based on your configuration. This test was done using the default configuration.

[eros]

Yes that's it, Thank you very much.. It is highly appreciated.

TOPIC CLOSED

[pbmods]

Heya, Eros.

Class variables are DECLARED using '$' notation, but they are ACCESSED using '$this->'.

When you do this:
[code=php]
protected $myVar;
[/code]

You are telling PHP to allocate memory for a protected variable named myVar.

The problem starts to manifest when you do something like this (which you should never do, but it is technically possible):
[code=php]
public function doSomething($my Var)
{
echo $myVar;
}
[/code]

What are we echoing here? The $myVar parameter to doSomething()? Or the protected member $myVar?

Hence, the $this notation:
[code=php]
public function doSomething($my Var)
{
echo $this->myVar;
}
[/code]

Since $this->myVar is the full reference to the variable, you only need to use one '$' sign.

Note that this would probably give you an error:
[code=php]
echo $this->$myVar;
[/code]
because PHP would evaluate $myVar, and then attempt to echo $this->{value of $myVar}.

For more info, check out this document.