MACROMEDIA FLEX-FLEX ACTIONSCRIPT LANGUAGE Reference page 215

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
thrown value is sent to the log file.
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
on page 55.)
// Define Error subclass InvalidEmailError
// In InvalidEmailError.as:
class InvalidEmailAddress extends Error {
var message = "Invalid email address.";
}
ActionScript Core Language Elements
or block, the string representation of the
catch finally
checks whether the string that is passed to it is
checkEmail()
function within a
checkEmail()
CHAPTER 5
code block.
catch{}
code block. If the
try
function is
checkEmail()
"Creating subclasses"
throw 215