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Learn how to dynamically call a function part of an instantiated ColdFusion Component (CFC) without relying on the `Evaluate()` function, enhancing the efficiency of your code.
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This video is based on the question https://stackoverflow.com/q/84463/ asked by the user 'Dan Roberts' ( https://stackoverflow.com/u/8345/ ) and on the answer https://stackoverflow.com/a/84836/ provided by the user 'Ben Doom' ( https://stackoverflow.com/u/12267/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Dynamically Call a Function in ColdFusion Without Using Evaluate()

In the world of programming, there are often challenges that can hold back productivity and creativity. For developers working with ColdFusion, one common question arises: How can I call a function dynamically that is part of an instantiated CFC without using Evaluate()? This is a legitimate concern that many encounter while trying to keep their code clean and efficient.

You may have tried to call a function in a way that seemed logical, only to realize that your method won't work. For example, attempting to use a line of code such as:

[[See Video to Reveal this Text or Code Snippet]]

may lead you to confusion. Let’s dive into the solution and explore how to overcome this challenge effectively.

Understanding the Problem

When you want to call a function dynamically based on its name stored in a variable, Evaluate() often seems like the straightforward solution. However, it is not always the best practice due to performance considerations and potential security issues. Instead, we want to find a method that allows us to invoke functions in a more efficient manner without creating new instances or using Evaluate().

The Solution

Creating a CFC Instance

First, you need to create an instance of your ColdFusion Component (CFC). This will serve as the object from which you will call methods dynamically. Here’s how you can create the CFC instance:

[[See Video to Reveal this Text or Code Snippet]]

In this example, tellTime2 is the name of your component, and tellTimeObj is the variable that will hold the instance of this component.

Invoking Methods Dynamically

Next, you can invoke methods on your CFC instance dynamically by referencing the method name via a variable. Instead of using the fixed method name, you can refer to it dynamically. Here’s how you can set this up:

[[See Video to Reveal this Text or Code Snippet]]

In the above code:

myMethod is the variable containing the name of the method you wish to call. This should be assigned a string that matches the method's name in your CFC.

resultVariable will hold the output of the invoked method.

Example in Action

Let’s consider a simple example where you have two methods in your CFC named getLocalTime and getUTCTime. You can dynamically call these methods as follows:

[[See Video to Reveal this Text or Code Snippet]]

Now, based on the value of myMethod, you can successfully call either getLocalTime or getUTCTime without creating a new instance or using Evaluate().

Conclusion

Dynamically calling a function in an instantiated CFC in ColdFusion can streamline your code and improve its efficiency. By employing the cfinvoke method along with variable method names, you can achieve dynamic function calls effectively.

This approach not only adheres to best practices but also promotes cleaner, more maintainable code. Embrace these techniques to take your ColdFusion programming to the next level!