1. Spreadsheets in Finance and Forecasting Presentation 11 Visual Basic

2. Objectives After studying this week’s work you will be able to: Use the Visual Basic Editor to examine and interpret VB Code Modify Macros in order to extend their role Communicate with the user via input and message boxes Allow the user to choose courses of actions

3. Introduction

4. VB Examples We will use a spreadsheet to examine the process of creating Visual Basic code via a macro. The example is a simple situation where we have new data to be used to update a total.

5. VB Examples One way of doing this is to incorporate the calculation into the spreadsheet formulae. Another way is to write a macro which does this (and undoes it) at the press of a button.

6. What you should know Before you start this work, you should have configured Excel with the VB toolbar. You also need to remember the methods introduced last week.

7. Section 1 Understanding VB Code

8. VB Examples Open the VB Examples Spreadsheet, and carry out the task described there Action Point

9. Excel Macros Excel Macros are recorded as routines in Visual Basic (VB) Code When we “run” macros, what we are doing is running short Visual Basic programs. During the rest of this presentation we will be working with this VB Code.

10. The Visual Basic Editor Click on: Tools – Macro- Visual Basic Editor The FoldersThe Visual Basic Code Action Point

11. Visual Basic Code -Features Title of the macro Comments are prefaced with a single quote mark, and appear in green End of macro Visual Basic Commands

12. Understanding the Code VB code is highly complex and would take you a long time to learn to write. However if you know what the code is doing, you can work out what each part does. 2. Write =J4+E4 in cell L4 3. Autofill L4:L8 4. Copy L4:L8 6. Delete L4:L8 5. Paste L4:L8 over to J4:J8

13. Understanding the Code We will now examine the code apart bit-by bit. Click the buttons to see what each section does J4 + L4 Autofill Copy Paste Delete Next Slide

14. Write “=J4+E4” in cell L4 This code comprises two lines: Range("L4").Select ActiveCell.FormulaR1C1 = "=RC[-2]+RC[-7]" The first line is simply a command to select cell L4, which then becomes the active cell.

15. Write “=J4+L4” in cell L4 Range("L4").Select ActiveCell.FormulaR1C1 = "=RC[-2]+RC[-7]" The second line puts a formula in this active cell. This cell is now regarded (for the moment) as Row 1 Column 1 In the formula, RC[-2] means “same Row”, but 2 Columns to the left Return

16. Autofill L4:L8 This takes two lines: Range("L4").Select Selection.AutoFill Destination:=Range("L4:L8"), Type:=xlFillDefault The first line simply selects cell L4 The second line (all three parts of it!) auto fills it down to L8 Return

17. Copy cells L4:L8 This takes two lines: Range("L4:L8").Select Selection.Copy The first line selects the range of cells from L4 to L8 The second line is an instruction to copy this selection. Return

18. Paste J4:J8 over to L4:L8 This takes two lines: Range("J4:J8").Select Selection.PasteSpecial Paste:=xlValues, Operation:=xlNone, SkipBlanks:= _ False, Transpose:=False The first line selects J4:J8, the range of cells to be copied.

19. Paste J4:J8 over to L4:L8 Range("J4:J8").Select Selection.PasteSpecial Paste:=xlValues, Operation:=xlNone, SkipBlanks:= _ False, Transpose:=False The second line is the Paste Special option, which pastes values only. Note that lots of other things are included in this that you might not have been aware of. Return

20. Delete L4:L8 This takes three lines of code Range("L4:L8").Select Application.CutCopyMode = False Selection.ClearContents The first line selects cells L4 to L8 The second line establishes that we are not going to cut or copy the cells. The third line clears the contents. Return

21. Working in Visual Basic As you can see, VB is not a simple language, and not something that you can immediately use. However, the usual way that people work is to record macros and use the code as a basis for what they want to do.

22. Section 2 Modifying VB Code

23. Your first Original Macro! Return to Sheet 1 of the VB Examples spreadsheet. You are going to write a macro which will subtract “Today’s Sales” from the “Total so far this month”.

24. Step 1: Copy and Rename Switch to VB Editor mode, and copy the entire “increaseTotal” macro Underneath the original, paste a second version, but change the title to “decreaseTotal” Action Point

25. Your first Original Macro! Now examine the macro You only need to change one symbol on one line That is the line which puts the formula into cell L4 ActiveCell.FormulaR1C1 = "=RC[-2]+RC[-7]"

26. Your first Original Macro! Make the change to the macro and assign it to the second button on the sheet. Check that it works. The line should read: ActiveCell.FormulaR1C1 = "=RC[-2]- RC[-7]" Instead of writing “=J4+L4”, we need to have this say “=J4-E4”

27. Section 3 Communicating with the User

28. Amending Macros It is often useful to send a message to the user to say that a macro has been completed. There is a simple piece of coding which allows you to do this

29. Adding a Message Box In the increaseTotal macro, just before the End Sub line, add the following: MsgBox “Task completed” Action Point

30. Adding a Message Box The line: MsgBox “Task completed” Generates this box The user needs to press the button to continue. The message box is a useful way to communicate with a user

31. Disabling the Message Box Add a single quotation mark, and change the line to: ‘ MsgBox “Task completed” Now click off the line; note that this turns the text green. If you now run the macro, the message box will not appear. This is because VB treats the line as a comment, not as a piece of code. Action Point

32. Section 4 Giving the user Choice

33. Giving the User Choice We will now write a completely new macro which will allow the user to choose whether to increase or decrease the “total so far” In doing this you will see how macros can be developed.

34. Recording a New Macro Record a macro called makeSelection This macro will consist of two button presses: Increase Total Decrease Total Action Point

35. The New Macro Sub makeSelection() ' ' makeSelection Macro ' Macro recorded 20/03/2002 by User Application.Run "'VB Examples - Solution.xls'!increaseTotal" Application.Run "'VB Examples - Solution.xls'!decreaseTotal" End Sub The macro simply consists of a title, an end, some comments in green, and two lines of code. Increase Total button Decrease Total button

36. Adding an Input Box Choice = InputBox(“increase or decrease?”) Application.Run "'VB Examples - Solution.xls'!increaseTotal" Application.Run "'VB Examples - Solution.xls'!decreaseTotal" After the green comments, but before the lines of VB code, insert the following: This will put an input box on the screen which will ask the user for a reply. Action Point

37. Adding choice Choice = InputBox(“increase or decrease?”) If choice = “inc” Then Application.Run "'VB Examples - Solution.xls'!increaseTotal" End If If choice = “dec” Then Application.Run "'VB Examples - Solution.xls'!decreaseTotal“ End If We will assume that the user will type in either “inc” or “dec” We now add lines which will allow the user to choose which action is carried out. 1 2 Action Point

38. Assigning the Macro Assign the Macro to the third button on the VB Examples Sheet. Run the macro. When the input box appears, type in either inc or dec Action Point

39. Finishing the Macro The macro carries out the task, but does not tell you that it has done it. Add code to the macro so that the correct one of these message boxes appears Action Point

40. makeSelection Macro Sub makeSelection() ' ' makeSelection Macro ' Macro recorded 20/03/2002 by User ' choice = InputBox("Do you want to Increase or Decrease?") If choice = "inc" Then Application.Run "'VB Examples - Solution.xls'!increaseTotal" MsgBox "Total Increased" End If If choice = "dec" Then Application.Run "'VB Examples - Solution.xls'!decreaseTotal" MsgBox "Total Decreased" End If End Sub The best place to put the message boxes is inside the “IF” commands

41. What have we learned? The macro we have just written is not all that useful, since we could just have pressed the buttons. However, suppose that we wanted to update one line selectively. With the commands, we could do this.

42. Section 5 Using Selections

43. Selective Updating Firstly, add numbers 1-5 to each of the type of item This will allow us to use a number rather than the name Action Point

44. Recording the initial macro Record a new macro called selectLine. This should: Put the formula =L4+E4 in cell L4 Copy L4 and Paste Values into K4 Delete L4 Sub selectLine() ' ' selectLine Macro ' Macro recorded 20/03/2002 by User ' Range("L4").Select ActiveCell.FormulaR1C1 = "=RC[-2]+RC[-7]" Range("L4").Select Selection.Copy Range("J4").Select Selection.PasteSpecial Paste:=xlValues Operation:=xlNone, SkipBlanks:= _ False, Transpose:=False Range("L4").Select Application.CutCopyMode = False Selection.ClearContents End Sub Action Point

45. Adding New Lines (1) At the beginning of the macro add these lines: The first asks the user which line is to be updated. The second identifies which cells will be modified. Line = InputBox("Which Line do you wish to update: 1,2,3,4,or 5") If Line = 1 Then cell1 = "L4" cell2 = "J4" End If Action Point

46. Adding New Lines (2) Now add these lines: These identify the cells which will be updated if the user selects line 2 or 3 Now add the lines needed if the user wants to update lines 4 or 5 If Line = 2 Then cell1 = "L5" cell2 = "J5" End If If Line = 3 Then cell1 = "L6" cell2 = "J6" End If Action Point

47. Modifying the code Modify the code underneath as follows: Wherever “L4” occurs, replace it with cell1 Wherever “J4” occurs, replace it with cell2 Range(cell1).Select ActiveCell.FormulaR1C1 = "=RC[-2]+RC[-7]" Range(cell1).Select Selection.Copy Range(cell2).Select Selection.PasteSpecial Paste:=xlValues, Operation:=xlNone, SkipBlanks:= _ False, Transpose:=False Range(cell1).Select Application.CutCopyMode = False Selection.ClearContents Action Point

48. Finishing off Finally, add a line just before the end: MsgBox "Line " & Line & " updated“ This will add a message box to say which line has been updated. Now, reassign the “Make Selection” button to the selectLine macro and test it out. Action Point

49. What Next? There are two separate Activity Sheets which follow up this work: Activity Sheet 10a creates macros which draw charts for selected lines of data Activity Sheet 10b explores how to update and interrogate a database