ActionScript 3.0 Language and Components Reference | All Packages | All Classes | Language Elements | Index | Appendixes | Conventions | Frames No Frames |
Error

Package | Top Level
Class | public dynamic class Error
Inheritance | Error Object
Subclasses | ArgumentError, DefinitionError, EvalError, IllegalOperationError, InvalidSWFError, IOError, MemoryError, RangeError, ReferenceError, ScriptTimeoutError, SecurityError, StackOverflowError, SyntaxError, TypeError, URIError, VerifyError

Language Version : | ActionScript 3.0

Player Version : | Flash Player 9

The Error class contains information about an error that occurred in a script. In developing ActionScript 3.0 applications, when you run your compiled code in the debugger version of Flash Player, a dialog box displays exceptions of type Error, or of a subclass, to help you troubleshoot the code. You create an Error object by using the `Error` constructor function. Typically, you throw a new Error object from within a `try` code block that is caught by a `catch` or `finally` code block.

You can also create a subclass of the Error class and throw instances of that subclass.

View the examples

See also

Working with the debugger version of Flash Player
Creating custom error classes
Responding to error events and status

Public Properties
Hide Inherited Public Properties
Show Inherited Public Properties

| Property | Defined By
--- | --- | ---
|  | constructor : Object A reference to the class object or constructor function for a given object instance. | Object
|  | errorID : int [read-only] Contains the reference number associated with the specific error message. | Error
|  | message : String Contains the message associated with the Error object. | Error
|  | name : String Contains the name of the Error object. | Error
|  | prototype : Object [static] A reference to the prototype object of a class or function object. | Object

Public Methods
Hide Inherited Public Methods
Show Inherited Public Methods

| Method | Defined By
--- | --- | ---
|  | Error(message:String = "", id:int = 0) Creates a new Error object. | Error
|  | getStackTrace():String Returns the call stack for an error as a string at the time of the error's construction (for the debugger version of Flash Player only). | Error
|  | hasOwnProperty(name:String):Boolean Indicates whether an object has a specified property defined. | Object
|  | isPrototypeOf(theClass:Object):Boolean Indicates whether an instance of the Object class is in the prototype chain of the object specified as the parameter. | Object
|  | propertyIsEnumerable(name:String):Boolean Indicates whether the specified property exists and is enumerable. | Object
|  | setPropertyIsEnumerable(name:String, isEnum:Boolean = true):void Sets the availability of a dynamic property for loop operations. | Object
|  | toString():String Returns the string "Error" by default or the value contained in Error.message property, if defined. | Error
|  | valueOf():Object Returns the primitive value of the specified object. | Object

Property Detail

errorID | property

`errorID:int` [read-only]

Language Version : | ActionScript 3.0

Player Version : | Flash Player 9

Contains the reference number associated with the specific error message. For a custom Error object, this number is the value from the `id` parameter supplied in the constructor.

Implementation
`public function get errorID():int`

message | property |

`public var message:String`

Language Version : | ActionScript 3.0

Player Version : | Flash Player 9

Contains the message associated with the Error object. By default, the value of this property is "`Error`". You can specify a `message` property when you create an Error object by passing the error string to the `Error` constructor function.

See also

statements.html#throw
statements.html#try..catch..finally

name | property |

`public var name:String`

Language Version : | ActionScript 3.0

Player Version : | Flash Player 9

Contains the name of the Error object. By default, the value of this property is "`Error`".

See also

statements.html#throw
statements.html#try..catch..finally
Constructor Detail

Error | () | Constructor

`public function Error(message:String = "", id:int = 0)`

Language Version : | ActionScript 3.0

Player Version : | Flash Player 9

Creates a new Error object. If `message` is specified, its value is assigned to the object's `Error.message` property.

Parameters

| `message:String` (default = "``")`` — A string associated with the Error object; this parameter is optional.
| `id:int` (default = `0`)`` — A reference number to associate with the specific error message.

See also

statements.html#throw
statements.html#try..catch..finally
Example
The following example creates a new Error object `err` and then, using the `Error()` constructor, assigns the string `"New Error Message"` to `err`.

    var err:Error = new Error();
    trace(err.toString());    // Error

    err = new Error("New Error Message");
    trace(err.toString());    // Error: New Error Message

Method Detail

getStackTrace | () | method

`public function getStackTrace():String`

Language Version : | ActionScript 3.0

Player Version : | Flash Player 9

Returns the call stack for an error as a string at the time of the error's construction (for the debugger version of Flash Player only). As shown in the following example, the first line of the return value is the string representation of the exception object, followed by the stack trace elements:

      TypeError: null cannot be converted to an object
          at com.xyz.OrderEntry.retrieveData(OrderEntry.as:995)
          at com.xyz.OrderEntry.init(OrderEntry.as:200)
          at com.xyz.OrderEntry.$construct(OrderEntry.as:148)

Returns

| `String` — A string representation of the call stack.

toString | () | method |

`override public function toString():String`

Language Version : | ActionScript 3.0

Player Version : | Flash Player 9

Returns the string `"Error"` by default or the value contained in `Error.message` property, if defined.

Returns

| `String` — The error message.

See also

Error.message
statements.html#throw
statements.html#try..catch..finally
Example
The following example creates a new Error object `err` and then, using the `Error()` constructor, assigns the string `"New Error Message"` to `err`. Finally, the `message` property is set to `"Another New Error Message"`, which overwrites `"New Error Message"`.

    var err:Error = new Error();
    trace(err.toString());    // Error

    err = new Error("New Error Message");
    trace(err.toString());    // Error: New Error Message

    err.message = "Another New Error Message";
    trace(err.toString());    // Error: Another New Error Message

Examples How to use examples
ErrorExample.as
The following example uses the `ErrorExample` class to show how a custom error can be generated. This is accomplished with the following steps:

1. A local variable `nullArray` of Array type is declared, but notice that a new Array object is never created.
2. The constructor attempts to load a value into the uninitialized array by using the `push()` method within an error handling code segment that catches a custom error by using the `CustomError` class, which extends `Error`.
3. When the CustomError is thrown, the constructor catches it and then outputs an error message by using the `trace()` statement.

    package
    {
        import flash.display.Sprite;
        public class ErrorExample extends Sprite
        {
            private var nullArray:Array;
            public function ErrorExample()
            {
                try
                {
                    nullArray.push("item");
                }
                catch(e:Error)
                {
                    throw new CustomError("nullArray is null");
                }
            }
        }
    }

    class CustomError extends Error
    {
        public function CustomError(message:String)
        {
            super(message);
        }
    }

Submit Feedback on LiveDocs
© 2004-2008 Adobe Systems Incorporated. All rights reserved.
Tue May 20 2008, 04:02 AM -07:00