# Expression Editor Elements

## Content

# Expression Editor Elements

The Expression Editor consists of three components:

* **C1ExpressionEditor**: Provides an expression text box where users can enter expressions
* **C1ExpressionEngine**: A non-UI engine responsible for validating and evaluating expressions. The C1ExpressionEditor relies on this engine for all calculations
* **C1ExpressionEditorPanel**: A quick-access toolbar with arithmetic and logical operator buttons, along with a categorized view of built-in functions, operators, and constants

### C1ExpressionEditor

**Expression TextBox**: A text box that enables user to create and edit expressions
**Error Box**: Shows the error information for the entered expression

### C1ExpressionEditorPanel

**Operator Buttons**: Buttons that represent shortcuts for operators
**Category Selection**: A tree view which contains available functions, operators, fields and constants
**Items**: A list box that lists the items selected from the Category Selection section
**Description Panel**: A panel that displays the description of the item selected from the Category Selection section
The following image illustrates constituting components of Expression Editor control and their respective elements.
![179a30a6-0cf7-455e-8a29-b6e0d4d3c9fe.png](https://cdn.mescius.io/document-site-files/images/169dc7b7-5d45-4ef3-9e8e-722266e38e9b/179a30a6-0cf7-455e-8a29-b6e0d4d3c9fe.db3a4a.png)