User Defined Function Example

by Synthiam

Example of how to create a plugin that becomes an ez-script function.

How to add the User Defined Function Example robot skill

  1. Load the most recent release of ARC (Get ARC).
  2. Press the Project tab from the top menu bar in ARC.
  3. Press Add Robot Skill from the button ribbon bar in ARC.
  4. Choose the Scripting category tab.
  5. Press the User Defined Function Example icon to add the robot skill to your project.

Don't have a robot yet?

Follow the Getting Started Guide to build a robot and use the User Defined Function Example robot skill.

How to use the User Defined Function Example robot skill

Add custom EZ-Script functions in c# using this example.

The source code is available here:

Additional tutorial information can be found here:

Optionally, you can create custom JavaScript functions with these instructions:

There is also an example code below the video.

using System;
using System.Drawing;
using System.Windows.Forms;

namespace User_Defined_Function_Example {

  public partial class FormMaster : EZ_Builder.UCForms.FormPluginMaster {

    public FormMaster() {


    private void FormMaster_Load(object sender, EventArgs e) {

      // Intercept all unknown functions called from any  EZ-Script globally.
      // If a function is called that doesn't exist in the  EZ-Script library, this event will execute
      ExpressionEvaluation.FunctionEval.AdditionalFunctionEvent += FunctionEval_AdditionalFunctionEvent;

    private void FormMaster_FormClosing(object sender, FormClosingEventArgs e) {

      // Disconnect from the function event
      ExpressionEvaluation.FunctionEval.AdditionalFunctionEvent -= FunctionEval_AdditionalFunctionEvent;

    /// This is executed when a function is specified in any ez-scripting that isn't a native function.
    /// You can check to see if the function that was called is your function.
    /// If it is, do something and return something.
    /// If you don't return something, a default value of TRUE is returned.
    /// If you throw an exception, the  EZ-Script control will receive the exception and present the error to the user.
    private void FunctionEval_AdditionalFunctionEvent(object sender, ExpressionEvaluation.AdditionalFunctionEventArgs e) {

      // Check if the function is our function (SetColor)
      if (!e.Name.Equals("setcolor", StringComparison.InvariantCultureIgnoreCase))

      // Check if the correct number of parameters were passed to this function
      if (e.Parameters.Length != 3)
        throw new Exception("Expects 3 parameters. Usage: SetColor(red [0-255], green [0-255], blue [0-255]). Example: SetColor(20, 200,100)");

      // Convert the parameters to datatypes
      byte red = Convert.ToByte(e.Parameters[0]);
      byte green = Convert.ToByte(e.Parameters[1]);
      byte blue = Convert.ToByte(e.Parameters[2]);

      // Do something
      EZ_Builder.Invokers.SetBackColor(label1, Color.FromArgb(red, green, blue));

      // Return something. Good idea to return TRUE if your function isn't meant to return anything
      e.ReturnValue = true;


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I see that I can create a user-defined function in C#. But I don't know C#. So, can I create a user-defined function using EZ-Script? If so, what is the syntax? I searched up and down and did not see anything on it. Otherwise, I guess I can just use lots and lots of "Script" skills.