July 1999

Naming Your ASP Variables with VBScript

In VBScript, the only variable type available is the variant. However, in most cases, you'll want to store a specific data type in a variable. To help avoid errors, and to make your code easier to read and easier to debug when things aren't working correctly, it's good practice to use a naming convention for all your variables. There are several conventions to choose from, and Table A lists one of many approaches. The advantage of this naming convention is that the data type is clear from the naming convention.

Table A: Variable naming convention

Data Type	Prefix	Example	VarType()
Boolean	bln	blnAccepted	11
Byte	byt	bytPixelValue	17
Date or Time	dtm or dat	dtmFirstTime	7
Double	dbl	dblTotalDistance	5
Error	err	errOverflow	10
Integer	int	intCount	2
Long	lng	lngFreeSpace	3
Object	obj	objListBox	9 or 13
Single	sng	sngLength	4
String	str	strAddress	8

The VarType function can be used to determine how a value is stored in a variant. The results for each of the variant types are shown in Table A.

This same type of naming convention is useful for controls, as well. Take a look at Table B; it shows a similar naming convention for controls.

Table B: Naming convention for controls

Control Type	Prefix	Example
Check Box	chk	chkFullPacksOnly
Combo List Box	cbo	cboThickness
Command Button	cmd or btn	cmdCalculate
Horizontal Scroll Bar	hsb	hsbWidth
Image Control	img	imgDisplayPicture
Label	lbl	lblDescription
List Box	lst	lstBrickTypes
Pop-up Menu	mnu	mnuSelection
Radio/Option Button	opt	optIncludeCement
Spin Button	spn	spnVolume
Tab Strip	tab	tabOptionPages
Text Box	txt	txtCustomer
Vertical Scroll Bar	vsb	vsbHeight

Notes As we mentioned previously, the variable naming convention is only one form of naming convention. If you have others you'd like to share, send them in to us at asp@zdjournals.com. Conclusion In this article, we showed you some useful naming conventions to help identify different variables and controls within your code. Hopefully you're able to use this information to help you avoid errors and make your code easier to understand.

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