The Expression Editor button displays the Expression Editor dialog box. You can use this dialog box to create expressions in two ways:

• If you are new to expressions, you can build them by double-clicking items in the lists in the top half of the dialog box in the proper order.
• If you are familiar with expression syntax, you can enter your expressions directly into the large editing field.

The Expression Editor dialog box enables you to create and validate expressions.

You can build several kinds of expressions. The following are the most common types of expressions:

• Calling a function on an interactive object: Here, you’re basically telling an object to do something. For example, to make a hidden object visible, you can call the SetVisible function on that object: MyBox.SetVisible(true)
• Assigning a value to a variable: Here, you’re changing a variable’s value. For example, you might assign the contents of a Text Box object to a variable named “UserName”: UserName = MyTextBox.GetText()

• Calling a function on an interactive object
• Assigning a value to a variable