CODEWITHSUNDEEP
coldfusion
volume one
volume one

Reputation: 7563

Why do we need to create an instance of a CFC?

I'm using the CreateObject() method to create an instance of a CFC and then interacting with this newly created 'instance'. I'm doing this because that's how it seems to be done, but I don't understand why we do this.

Why can't we just interact with the CFC directly instead of creating an instance of it?

Upvotes: 2

Views: 179

Answers (3)

Dan Bracuk
Dan Bracuk

Reputation: 20804

You can call the cfc directly using cfinvoke. You just have to realize that cfinvoke creates an object of the cfc first, then executes the method you invoked. Also, once the method is invoked, the object is no longer available.

If your .cfm page is only going to use one method of the component, cfinvoke is ok because there is less code for you to write. However, if you use two or more, it's less efficient because a new object has to be created each time.

In other word, while you don't have to create an instance of the cfc first, it's often a good idea to do so.

Upvotes: 4

CFML_Developer
CFML_Developer

Reputation: 1605

I hope you have read OOPs and its practices. CFC is your 'blueprint' (say a car design) and object is your own data model (say a car of blue color (method to set color), with nitrogen filled tires (method to set pressure in tires) and runs on LPG (method for fuel type)). CF allow you interact directly with CFC (CFINVOKE) and you do not have to create an instance each time but it just only make sense that you would not want to go to workshop/design lab each time you want to change a configuration for your car.

Upvotes: 3

Adam Cameron
Adam Cameron

Reputation: 29870

A CFC is just a file with some code in it, so it makes little sense to suggest "interacting" with it, just the same as you might suggest "interacting" with a CFM file without <cfinclude>-ing it or similar.

A CFC defines a component, and to use a component, one creates an instance of it. In some languages - eg Java - one can have static properties and methods, and one can access them via the class rather than necessarily object, but CFML does not have this concept. CFCs define components which are used as objects, just the same as in other languages a class defines what it is to be an object, and to use an object, one first needs to create an instance of it.

Upvotes: 5

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