Introduction to VB Function

The main purpose of the functions is to accept certain inputs and pass them on to the main program to finish the execution and also are similar to normal procedures but. They are two types of function, the functions created by the programmers and the built-in functions(or internal functions).

The general format of a function is

functionName(arguments)

where arguments are values that are passed on to functions.

In this lesson, we are going to learn two very basic but useful internal functions, i.e. InputBox ( ) function and sthe MsgBox( ).

1.MsgBox ( ) Function

The objective of MsgBox is to prompt the user to click on a command button before he /she can continues and produce a pop-up message box. This message box format is as follows:

yourMsg=MsgBox(Prompt, Style Value, Title)

The first argument in the above format, Prompt, will display the message in the message box and the Style Value will determine what type of command buttons appear on the message box, please refer to table which is given below for types of command button displayed. The Title argument will display title of the message board.

Style Value	Named Constant	Buttons Displayed
0	vbOkOnly	Ok button
1	vbOkCancel	Ok and Cancel buttons
2	vbAbortRetryIgnore	Abort, Retry and Ignore buttons.
3	vbYesNoCancel	Yes, No and Cancel buttons
4	vbYesNo	Yes and No buttons
5	vbRetryCancel	Retry and Cancel buttons

Table below shows the values, the corresponding named constant and buttons.

Value	Named Constant	Button Clicked
1	vbOk	Ok button
2	vbCancel	Cancel button
3	vbAbort	Abort button
4	vbRetry	Retry button
5	vbIgnore	Ignore button
6	vbYes	Yes button
7	vbNo	No button

The following example shows the use of MsgBox ( ) Function in VB

Private Sub Test_Click()
Dim testmsg As Integer
testmsg = MsgBox("Click to test", 1, "Test message")
If testmsg = 1 Then
Display.Caption = "Testing Successful"
Else
Display.Caption = "Testing fail"
End If
End Sub

O/P:

There are four types of icons available in VB as shown in the following table:

Value	Named Constant	Icon
16	vbCritical
32	vbQuestion
48	vbExclamation
64	vbInformation

The following example shows the use of VB Icons

Private Sub test2_Click()

Dim testMsg2 As Integer
testMsg2 = MsgBox("Click to Test", vbYesNoCancel + vbExclamation, "Test Message")
If testMsg2 = 6 Then
display2.Caption = "Testing successful"
ElseIf testMsg2 = 7 Then
display2.Caption = "Are you sure?"
Else
display2.Caption = "Testing fail"
End If

End Sub

O/P:

2.The InputBox( ) Function

An InputBox( ) function will display a message box where the user can enter a message in the form of text or a value. The format is as follows:

myMessage=InputBox(Prompt, Title, default_text, x-position, y-position)

myMessage is a variant data type but typically it is declared as string and this accept the message input by the users. The arguments are explained as follows: follows:

Prompt - The message displayed normally as the question asked.
Title - The title of Input Box.
default-text - The default text that appears in the input field where users may change to the message he wish to key in and he can use it as his intended input.
x-position and y-position - the coordinate or the position of the input box.

The following example shows the use of InputBox( ) Function in VB

Private Sub OK_Click()
Dim userMsg As String
userMsg = InputBox("What is your message?", "Message Entry Form", "Enter your messge here", 500, 700)
If userMsg <> "" Then
message.Caption = userMsg
Else
message.Caption = "No Message"
End If

End Sub

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