Err.Raise Method

   
Err.Raise Method

Class

Microsoft.VisualBasic.ErrObject

Syntax

 Err.Raise(   number, source, description   , _   helpfile, helpcontext   ) 
number (required; Long integer)

A numeric identifier of the particular error

source (optional; String)

The name of the object or application responsible for generating the error

description (optional; String)

A useful description of the error

helpfile (optional; String)

The fully qualified path of a Microsoft Windows Help file containing help or reference material about the error

helpcontext (optional; Long)

The context ID within helpfile

Description

Generates a runtime error

Rules at a Glance

  • To use the Err.Raise method, you must specify an error number.

  • If you supply any of the number , source , description , helpfile , and helpcontext arguments when you call the Err.Raise method, they are supplied as values to the Number, Source, Description, HelpFile, and HelpContext properties, respectively. Refer to the entries for the individual properties for full descriptions of and rules for each property.

  • The number argument is a Long integer that identifies the nature of the error. Visual Basic errors (both Visual Basic-defined and user-defined errors) are in the range 0-65535. The range 0-512 is reserved for system errors; the range 513-65535 is available for user -defined errors. When setting the Number property to your own error code in a class module, you add your error-code number to the vbObjectError constant.

Programming Tips and Gotchas

  • The Err.Raise method replaces the older Error statement, which should not be used in new code.

  • The Raise method does not reinitialize the Err object prior to assigning the values you pass in as arguments. This can mean that if you Raise an error against an Err object that has not been cleared since the last error, any properties for which you don't specify values will still contain the values from the last error.

  • As well as using Raise in a runtime scenario, you can put it to good use in the development stages of your program to test the viability of your error-handling routines under various circumstances.

  • The fact that Err.Number only accepts numbers in the range 0-65536 may appear to be strange at first because the data type of the Error Number parameter in the Raise event is a Long. However, deep in the recesses of the Err object, the error code must be declared as an unsigned integer a data type not supported by VB.

See Also

Err.Clear Method

   


VB.Net Language in a Nutshell
VB.NET Language in a Nutshell
ISBN: B00006L54Q
EAN: N/A
Year: 2002
Pages: 503

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