Class

IllegalCastException

Description

Occurs when you attempt to cast a Variant or object to an incompatible object type.

Properties

Name	Type	Read-Only	Shared
ErrorNumber	Integer
Message	String

Methods

Name	Parameters	Returns
Constructor	message As String = "", errorNumber As Integer = 0
Stack		String()
StackFrames		StackFrame()

Property descriptions

IllegalCastException.ErrorNumber

ErrorNumber As Integer

Used to contain an error number that describes the runtime error.

IllegalCastException.Message

Message As String

Used to contain descriptive text to display when the runtime exception is encountered.

Method descriptions

IllegalCastException.Constructor

Constructor(message As String = "", errorNumber As Integer = 0)

Note

Constructors are special methods called when you create an object with the New keyword and pass in the parameters above.

Used to raise your own RuntimeException with a message and optional error number.

IllegalCastException.Stack

Stack As String()

Returns a String array that contains a list of all of the methods in the stack from the main entrypoint to the point at which the exception was invoked.

The stack contains all the method names up and including the current method name.

This feature only works if the IncludeFunctionNames property on the App object is selected in the Shared Build Settings.

In addition to your own method calls, you will also see framework method calls, but these may not always be completely accurate due to insufficient symbols for the OS to resolve.

IllegalCastException.StackFrames

StackFrames As StackFrame()

Returns an array containing the stack when the exception was first raised.

Notes

An IllegalCastException occurs when you attempt to cast a Variant or object to an incompatible object type. The exception is thrown at the point of the cast itself, regardless of whether any methods or properties are subsequently accessed.

For example, casting a DesktopBevelButton as a DesktopButton throws an IllegalCastException because a DesktopBevelButton is not a DesktopButton.

An IllegalCastException also occurs when assigning a Variant to an incompatible object type:

Try // Variant containing a scalar assigned to an object type
  Var v As Variant = 123
  Var d As Dictionary = v
Catch Err As IllegalCastException
End Try

Try // Variant containing an object assigned to an incompatible object type
  Var v As Variant = New Picture(1, 1)
  Var d As Dictionary = v
Catch Err As IllegalCastException
End Try

See TypeMismatchException for the related exception that occurs when assigning a Variant to an incompatible scalar type.

Sample code

This example attempts to cast a DesktopBevelButton as a DesktopButton then call the Press method of the DesktopButton class. This example assumes that there is a DesktopBevelButton called "BevelButton1" in the same window where this code is being called:

Var c As DesktopUIControl
c = BevelButton1
DesktopButton(c).Press

When you test this code in the IDE, execution will stop at the last line and display an IllegalCastException error in your Code editor. If you test the code in a standalone app, the application will display a generic error message and quit when the user clicks OK.

You can handle the error by adding an Exception block to your code:

Var c As DesktopUIControl
c = BevelButton1
DesktopButton(c).Press
Exception err
  If err IsA IllegalCastException Then
    MessageBox("Trying to recast a DesktopBevelButton as DesktopButton!")
  End If

Compatibility

Project Types	All
Operating Systems	All