Visual Basic Tutorial

Message Boxes

Objectives

This guide  will help you to: -  

• Use message boxes in your application
  

Introduction

Displaying a Message Box

       Adding a Title

       Choosing a Button Style

       Choosing an Icon Style

Using Return Values

Help Desk Exercise

Introduction

Message boxes are typically used when you want to ask the user a question or display an error message. There are six types of message boxes.  You will learn how to use the more common types.

Displaying a Message Box

The syntax for displaying a message box is

 MgsgBox "THE MESSAGE"

To try it out - add an empty form to one of your VB projects.  Don't forget to make it the start-up form.

Add a command button to your form.  Leave it with the default name of 'Command1'

Now lets add code to display a message box.  Double-click the command button on your form.  This should take you to the coding window.  Type in the following:-

When you run your program and click on the command button you should see the following:-

Adding a Title

You can also add a title to your message box.  Change your code to the following:-

Now you should a message like the one shown below.  Notice the Title of the message box.

Choosing a Button Style

You can also decide what style of message box you want.  This means you can specify what buttons your message box should contain.  You have a few different choices such as an OK button only, or an OK and Cancel button.  Or perhaps you would prefer Yes/No buttons.   Here are a few examples.

Now you should a message like the one shown below.

Now try this one:-

Now you should a message like the one shown below.

There are other buttons you can have.  Look at the list in the table below and experiment for yourself.

Choosing an Icon Style

As well as choosing a button style, you can also choose an icon style.  Let's have a couple of examples:-

Now you should a message like the one shown below.

Or how about this one:-

Now you should a message like the one shown below.

There are other icons you can have.  Look at the list in the table below and experiment for yourself.

Using Return Values

If your message box just displays information to a user and there is only an OK button then you do not have to add any more code.  What happens though if your message box has Yes/No buttons or OK/Cancel buttons?  Then you will need to know which button the user clicked when they dismissed the message box.

To know which button the user clicked when they closed the message box you have to catch the return value.  Here is an example:-

Notice how I have now included brackets in the MsgBox line -

MsgBox ("Do you really want to reformat your C: drive?", vbYesNo + vbQuestion)

You only have to do this if you want to get the return value. The line below does not include the brackets because I don't want the return value:-

MsgBox "You clicked Yes"

Now you should a message like the one shown below.

	You also get another message box depending on whether you click the Yes or No button.

Of course, you don't have to display more message boxes when the user clicks on the Yes or No button.  What happens when they click on a button is up to you.  You just have to specify the action you want in the IF-Else part of the code.  I.e. This part...

If response = vbYes Then   ' User chose Yes.
    ' Put code in here to perform some action.
Else ' User chose No.
    ' Put code in here to perform a different  action.
End If

Just to finish off, the return values for the different buttons are listed in the table below.

Just to be clear. If you have an OK/Cancel button pair, to check which button the user clicked you could use an IF-Else block like this:-

If response = vbOK Then   ' User chose Yes.
    ' Put code in here to perform some action.
Else ' User chose No.
    ' Put code in here to perform a different  action.
End If

Why not experiment for yourself.

Help Desk Exercise

It is your turn to create a 'message boxes' for your 'help desk' application.  

Deciding when you need to display message boxes in your application is really up to you.  It is useful to display messages when you think you need to inform the user of some useful information, or if the user has committed some error which you need to tell them about, or if you need to give the user some advice.

Here are a few suggestions:-

~Try the activity~

Activity A

Have you created your 'Fault Log' form? If so, you should display a message informing the user if they forget to fill in one of the textboxes or fill in the textboxes with the wrong type of information, such as characters instead of say numbers.

~Try the activity~

Fini