The Daily Newbie - Using the Choose() Function

Description

04/28/2001 - Describes the usage of the Choose() function; A really neat but seldom used command in VB.

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Submitted On
By	Matthew Roberts
Level	Beginner
User Rating	4.5 (27 globes from 6 users)
Compatibility	VB 3.0, VB 4.0 (16-bit), VB 4.0 (32-bit), VB 5.0, VB 6.0, VB Script, ASP (Active Server Pages) , VBA MS Access, VBA MS Excel
Category	Coding Standards
World	Visual Basic
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<title>Daily Newbie - 04/28/2001</title>

 

The Daily Newbie

“To Start Things Off Right”

Fourth Edition                                                          April 28, 2001                                                                          Free

 

 

About this feature:

The initial plan for the Daily Newbie was to cover each function VB has to offer in alphabetical order. I have now modified this plan slightly to skip over some of the more advanced (or tedious) commands that I don't think the Newbie would benefit from. Thanks again all who have written in support of this effort. It makes a difference.

Today's command is not widely known for some reason, but is faily useful. I have been guilty of writing functions that do the exact same thing several times. I think you will like this one.

Today’s Keyword:                               Choose()

Name Derived From:                  

Choose (of course) – “(1) : to make a selection" - Webster's online dictionary.

Used for                                   Making a choice between several possible options.

VB Help Description:             Selects and returns a value from a list ofarguments.

Plain English:                           Returns the option associated with the value passed it (I will just have to show you!)

Syntax:                                     Choose(index, Choice1, Choice2, etc...)

Usage:                                      strDecision = Choose(intChoice ,  "Just do it" ,  "Don't do it" ,  "It's your life" )  

Copy & Paste Code:

Today's code snippet will prompt for a month number and return a string that corresponds to it.

 Dim Choice
 Dim strMonth As String
  Do
  Choice = Val(InputBox("Enter a Number (1-12):"))
  If Choice + 0 = 0 Then Exit Do
  strMonth = Choose(Choice, "Jan", "Feb", "Mar", "Apr", _
    "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec")
  MsgBox strMonth
  Loop

 

Notes: 

I really like the Choose function. It comes in handy for with evaluating which option button was clicked, or anything else that returns an index number. Unfortunatly, like the Array() command covered a couple of articles ago, the Choose() function requires a seperate hard coded value for each possible choice. This isn't neccesarily a bad thing, but I am allergic to hard coding, so it just rubs me wrong. I guess the chances of the order of the months changing is pretty slim...

Things to watch out for: 

Although the Choose() Statement only returns a single value, it still evaluates each one. In effect, it acts like a compact series of If...Then statements. This can result in the sometimes baffling behavior of displaying one message box with the correct value and many empty ones. For this reason, the results of a Choose() statement should be returned to a variable before displaying it in a message box.

If the Index value passed in is null, an error will result. Therefore, if you are using a variant as your Index, you should add zero to it to initialize it as a number. This will make the default value zero, not null.

Tomorrow's Keyword: Chr()