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Sunday, January 27, 2008

The Course Booking Form

The Course Booking Form is a simple form illustrating the principles of UserForm design and the associated VBA coding.

It uses a selection of controls including textbox, combo boxes, option buttons grouped in a frame, check boxes and command buttons.

When the user clicks the OK button their input is entered into the next available row on the worksheet.

Description of the Form:

There are two simple text boxes (Name: and Phone:) into which the user can type free text, and two combo boxes (Department and Course) that let the user to pick an item from the list.

There are three option buttons (Introduction, Intermediate and Advanced) grouped in a frame (Level) so that the user can choose only one of the options.

There are two check boxes (Lunch Required and Vegetarian) that, because they are not grouped in a frame, can both be chosen if required. However, if the person making the booking does not want lunch we do not need to know whether or not they are vegetarian. So, the Vegetarian check box is greyed-out until required.

There are three command buttons (OK, Cancel and Clear Form) each of which performs a pre-defined function when clicked.

The Control Properties Settings:

Control

Type

Property

Setting

UserForm

UserForm

Name

frmCourseBooking



Caption

Course Booking Form

Name

Text Box

Name

txtName

Phone

Text Box

Name

txtPhone

Department

Combo Box

Name

cboDepartment

Course

Combo Box

Name

cboCourse

Level

Frame

Name

fraLevel



Caption

Level

Introduction

Option Button

Name

optIntroduction

Intermediate

Option Button

Name

optIntermediate

Advanced

Option Button

Name

optAdvanced

Lunch Required

Check Box

Name

chkLunch

Vegetarian

Check Box

Name

chkVegetarian



Enabled

False

OK

Command Button

Name

cmdOk



Caption

OK



Default

True

Cancel

Command Button

Name

cmdCancel



Caption

Cancel



Cancel

True

Clear Form

Command Button

Name

cmdClearForm

Building the Form

If you want to build the form yourself, simply copy the layout shown in the illustration above. Follow the steps below:

1. Open the workbook that you want the form to belong in (UserForms like macros have to be attached to a workbook) and switch to the Visual Basic Editor.

2. In the Visual Basic Editor click the Insert UserForm button (or go to Insert > UserForm).

3. If the toolbox does not appear by itself (first click the form to make sure it isn’t hiding) click the Toolbox button (or go to View > Toolbox).

4. To place a control on the form click the appropriate button on the toolbox then click the form. Controls can be moved by dragging them by their edges, or resized by dragging the buttons around their perimeter.

5. To edit the properties of a control, make sure the chosen control is selected then make the appropriate changes in the Properties window. If you can’t see the properties window go to View > Properties Window.

6. To remove a control from the form, select it and click the Delete key on your keyboard.

A UserForm will not actually do anything until the code that drives the form and its various controls is created. The next step is to write the code that drives the form itself.

Adding the Code: 1 Initialising the Form

Initialising the Form:

Most forms need some kind of setting up when they open. This may be setting default values, making sure field are empty, or building the lists of combo boxes. This process is called Initialising the Form and it is taken care of by a macro called UserForm_Initialize (in case you are confused by my varying spelling of the word "initialis(z)e", it's because I speak English and VBA speaks American - but don't worry, VBA will spell it for you!). Here's how to build the code to initialise the Course Booking Form:

1. To view the form’s code window go to View > Code or click F7.

2. When the code window first opens it contains an empty UserForm_Click() procedure. Use the drop-down lists at the top of the code window to choose UserForm and Initialize. This will create the procedure you need. You can now delete the UserForm_Click() procedure.

3. Enter the following code into the procedure:

Private Sub UserForm_Initialize()

txtName.Value = ""

txtPhone.Value = ""

With cboDepartment

.AddItem "Sales"

.AddItem "Marketing"

.AddItem "Administration"

.AddItem "Design"

.AddItem "Advertising"

.AddItem "Dispatch"

.AddItem "Transportation"

End With

cboDepartment.Value = ""

With cboCourse

.AddItem "Access"

.AddItem "Excel"

.AddItem "PowerPoint"

.AddItem "Word"

.AddItem "FrontPage"

End With

cboCourse.Value = ""

optIntroduction = True

chkLunch = False

chkVegetarian = False

txtName.SetFocus

End Sub

How the Initialise Code Works:

The purpose of the UserForm_Initialize() procedure is to prepare the form for use, setting the default values for the various controls and creating the lists that the combo boxes will show.

These lines set the contents of the two text boxes to empty:

txtName.Value = ""

txtPhone.Value = ""

Next come the instructions for the combo boxes. First of all the contents of the list are specified, then the initial value of the combo box is set to empty.

With cboDepartment

.AddItem "Sales"

.AddItem "Marketing"

(as many as necessary…)

End With

cboDepartment.Value = ""

If required an initial choice can be made from the option group, in this case:

optIntroduction = True

Both check boxes are set to False (i.e. no tick). Set to True if you want the check box to appear already ticked:

chkLunch = False

chkVegetarian = False

Finally, The focus is taken to the first text box. This places the users cursor in the text box so that they do not need to click the box before they start to type:

txtName.SetFocus

Adding the Code: 2 Making the Buttons Work

There are three command buttons on the form and each must be powered by its own procedure. Starting with the simple ones…

Coding the Cancel Button:

Earlier, we used the Properties Window to set the Cancel property of the Cancel button to True. When you set the Cancel property of a command button to True, this has the effect of "clicking" that button when the user presses the Esc key on their keyboard. But this alone will not cause anything to happen to the form. You need to create the code for the click event of the button that will, in this case, close the form. Here's how:

1. With the UserForm open for editing in the Visual Basic Editor, double-click the Cancel button. The form's code window opens with the cmdCancel_Click() procedure ready for editing.

2. The code for closing a form is very simple. Add a line of code to the procedure so it looks like this:

Private Sub cmdCancel_Click()

Unload Me

End Sub

Coding the Clear Form Button:

I added a button to clear the form in case the user wanted to change their mind and reset everything, and to make it easier if they had several bookings to make at one time. All it has to do is run the Initialise procedure again. A macro can be told to run another macro (or series of macros if necessary) by using the Call keyword:

1. Double-click the Clear Form button. The form's code window opens with the cmdClearForm_Click() procedure ready for editing.

2. Add a line of code to the procedure so it looks like this:

Private Sub cmdClearForm_Click()

Call UserForm_Initialize

End Sub

Coding the OK Button:

This is the piece of code that has to do the job of transferring the user's choices and text input on to the worksheet. When we set the Cancel button's Cancel property to True we also set the OK button's Default property to True. This has of clicking the OK button when the user presses the Enter (or Return) key on their keyboard (providing they have not used their Tab key to tab to another button). Here's the code to make the button work:

1. Double-click the OK button. The form's code window opens with the cmdOK_Click() procedure ready for editing.

2. Edit the procedure to add the following code:

Private Sub cmdOK_Click()

ActiveWorkbook.Sheets("Course Bookings").Activate

Range("A1").Select

Do

If IsEmpty(ActiveCell) = FalseThen

ActiveCell.Offset(1, 0).Select

End If

Loop Until IsEmpty(ActiveCell) = True

ActiveCell.Value = txtName.Value

ActiveCell.Offset(0, 1) = txtPhone.Value

ActiveCell.Offset(0, 2) = cboDepartment.Value

ActiveCell.Offset(0, 3) = cboCourse.Value

If optIntroduction = True Then

ActiveCell.Offset(0, 4).Value = "Intro"

ElseIf optIntermediate = True Then

ActiveCell.Offset(0, 4).Value = "Intermed"

Else

ActiveCell.Offset(0, 4).Value = "Adv"

End If

If chkLunch = True Then

ActiveCell.Offset(0, 5).Value = "Yes"

Else

ActiveCell.Offset(0, 5).Value = "No"

End If

If chkVegetarian = True Then

ActiveCell.Offset(0, 6).Value = "Yes"

Else

If chkLunch = False Then

ActiveCell.Offset(0, 6).Value = ""

Else

ActiveCell.Offset(0, 6).Value = "No"

End If

End If

Range("A1").Select

End Sub

How the CmdOK_Click code works:

The first two lines make sure that the correct workbook is active and moves the selection to cell A1:

ActiveWorkbook.Sheets("Course Bookings").Activate

Range("A1").Select

The next few lines moves the selection down the worksheet until it finds an empty cell:

Do

If IsEmpty(ActiveCell) = False Then

ActiveCell.Offset(1, 0).Select

End If

Loop Until IsEmpty(ActiveCell) = True

The next four lines start to write the contents of the form on to the worksheet, using the active cell (which is in column A) as a reference and moving along the row a cell at a time:

ActiveCell.Value = txtName.Value

ActiveCell.Offset(0, 1) = txtPhone.Value

ActiveCell.Offset(0, 2) = cboDepartment.Value

ActiveCell.Offset(0, 3) = cboCourse.Value

Now we come to the option buttons. These have been placed in a frame on the form so the user can choose only one. An IF statement is used to instruct Excel what to for each option:

If optIntroduction = True Then

ActiveCell.Offset(0, 4).Value = "Intro"

ElseIf optIntermediate = True Then

ActiveCell.Offset(0, 4).Value = "Intermed"

Else

ActiveCell.Offset(0, 4).Value = "Adv"

End If

VBA IF statements are much easier to manage than Excel's IF function. You can have as many options as you want, just insert an additional ElseIf for each one. If there were only two options, you wouldn't need the ElseIf, just the If and Else would suffice (don't forget - they all need an End If).

There is another IF statement for each check box. For the Lunch Required check box, a tick in the box means "Yes" the person requires lunch, and no tick means "No" they don't.

If chkLunch = True Then

ActiveCell.Offset(0, 5).Value = "Yes"

Else

ActiveCell.Offset(0, 5).Value = "No"

End If

We could use a similar IF statement for the Vegetarian check box, but if the person does not require lunch it is irrelevant whether or not they are vegetarian. I any case, it would be wrong to assume that they were not vegetarian simply because they did not require lunch. The IF statement therefore contains a second, nested if statement:

If chkVegetarian = True Then

ActiveCell.Offset(0, 6).Value = "Yes"

Else

If chkLunch = False Then

ActiveCell.Offset(0, 6).Value = ""

Else

ActiveCell.Offset(0, 6).Value = "No"

End If

End If

A tick in the box means "Yes" the person is vegetarian. If there is no tick in the box, the nested IF statement looks at the Lunch Required check box. If the Lunch Required check box has a tick in it then no tick in the Vegetarian check box means that the person is not vegetarian so it inserts "No" into the cell. However, if the Lunch Required check box does not have a tick in it, then we do not know whether or not the person is vegetarian (it doesn't matter anyway) so the cell is left blank ("").

Finally the selection is taken back to the beginning of the worksheet, ready for the next entry:

Range("A1").Select

Adding the Code 3: Manipulating the Form

Finally, an example of how the controls on a form can be manipulated whilst it is in use. When the control properties were set, the Enabled property of the Vegetarian check box was set to False. When a control is not enabled the user cannot enter a value into it, although it can hold a value that was there already, and VBA can add, remove or change the value.

We don't need to know whether or not the person is vegetarian (even if they are!) if they aren't ordering lunch. So, the Vegetarian check box remains disabled unless a tick is placed in the Lunch Required check box. Then the user is free to tick the Vegetarian check box if they want to. If they tick it we will know that they have answered "Yes" and if they don't we know they have answered "No".

We can toggle the Enabled property from False to True by having a procedure that runs automatically whenever the value of the Lunch Required check box changes. Fortunately, more controls have a Change procedure and the one we use here is chkLunch_Change(). We'll use this to enable the Vegetarian check box when the Lunch Required check box is ticked, and disable it when the Lunch Required check box is not ticked.

There's just one more thing we need to do. Supposing someone ticked the Lunch Required check box, and also ticked the Vegetarian check box. Then they changed their mind and removed the tick from the Lunch Required check box. The Vegetarian check box would be disabled but the tick that was put in earlier would remain.

An extra line of code can make sure the tick is removed when the box is disabled. Here's the whole thing:

Private Sub chkLunch_Change()

If chkLunch = True Then

chkVegetarian.Enabled = True

Else

chkVegetarian.Enabled = False

chkVegetarian = False

End If

End Sub

Opening the Form

The form is now ready for use so it needs to be opened with a simple macro. That can be attached to a custom toolbar button, a command button drawn on the worksheet, or any graphic (right click the graphic and choose Assign Macro). If necessary, create a new module for the workbook and add this procedure:

Sub OpenCourseBookingForm()

frmCourseBooking.Show

End Sub



Author:
-----------------------
Kazi Masudul Alam
Software Engineer