Throw - MACROMEDIA FLASH MX 2004-ACTIONSCRIPT LANGUAGE Reference

throw

Availability
Flash Player 7.
Usage
throw expression
Description
Statement; generates, or throws, an error that can be handled, or caught, by a
If an exception is not caught by a
sent to the Output panel.
Typically, you throw instances of the Error class or its subclasses (see the Example section).
Parameters
An ActionScript expression or object.
expression
Example
In this example, a function named
a properly formatted e-mail address. If the string does not contain an @ symbol, the function
throws an error.
function checkEmail(email:String) {
if (email.indexOf("@") == -1) {
throw new Error("Invalid email address");
}
}
checkEmail("someuser_theirdomain.com");
The following code then calls the
string does not contain a valid e-mail address, the error message appears in a text field
email_txt
( ).
error_txt
try {
checkEmail("Joe Smith");
} catch (e) {
error_txt.text = e.toString();
}
In the following example, a subclass of the Error class is thrown. The
modified to throw an instance of that subclass. (For more information, see "Creating subclasses"
in Using ActionScript in Flash.)
// Define Error subclass InvalidEmailError
// In InvalidEmailError.as:
class InvalidEmailAddress extends Error {
var message = "Invalid email address.";
}
In a FLA or AS file, enter the following ActionScript in Frame 1 of the Timeline:
import InvalidEmailAddress;
function checkEmail(email:String) {
980 Chapter 2: ActionScript Language Reference
ActionScript Language Reference
block, the string representation of the thrown value is
catch
checks whether the string that is passed to it is
checkEmail()
function within a
checkEmail()
CHAPTER 2
code block.
catch{}
code block. If the
try
function is
checkEmail()