Learn Access 2003 VBA with The Smart Method

94

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Lesson 5-3: Understand

arguments

An argument is a value that may be passed to a sub or function.

Arguments usually modify the behavior of the sub or function in some

way.

In this lesson we’ll refine our ThankYouMessage sub even further by

adding two arguments to it.

1

Open the VBACode.mdb database (if not already open) and

open frmTest in Design View.

2

Open the VBA Editor.

Right click on the Command Button and select Build Event from

the shortcut menu. The code for the Command Button’s Click

event is displayed in the code editor.

3

Add an argument to the ThankYouMessage sub.

Edit the code so that it is the same as the following:

Private Sub cmdPressMe_Click()

Dim strMessage As String

strMessage = "Thank you for pressing me"

Call ThankYouMessage(strMessage)

End Sub

Sub ThankYouMessage(strMessage As String)

Beep

Call MsgBox(strMessage)

End Sub

Consider what is now happening. The strMessage variable is being

passed as an argument from the cmdPressMe_Click() event

handler to the ThankYouMessage sub.

4

Add a second argument to the ThankYouMessage sub to

allow a title to be specified.

Edit the code so that it is the same as the following:

Private Sub cmdPressMe_Click()

Dim strMessage As String

Dim strTitle As String

strMessage = "Thank you for pressing me"

strTitle = "Thank You"

Call ThankYouMessage(strMessage, strTitle)

End Sub

Sub ThankYouMessage(strMessage As String, _

strTitle As String)

Beep

Call MsgBox(strMessage,,strTitle)

Session5a

note

Some programmers prefer the

term Parameter instead of

Argument. Both are correct.

Session Five: Professional Grade VBA

© 2007 The Smart Method Ltd

95

End Sub

Passing the arguments is quite straightforward. There are simply

two arguments now instead of one.

Note that the MsgBox function has two commas between the

strMessage and strTitle arguments rather than one. This is because

the MsgBox function accepts the Title as its third argument, the

second argument is optional.

Note also the continuation character (an underscore) after the first

argument declaration for the ThankYouMessage sub.

Use continuation characters to break up long lines of code so that

they can be viewed within the code editor window without having

to use the scrollbars.

5

Test the command button.

Switch to Form View. When you click the command button you

should still hear a beep and see the message and title displayed in

a dialog box.

This proves that both your arguments are being passed correctly.