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21.04.23
1
VBA
(Visual Basic for Applications)
What is Excel, just a spreadsheet?
Time for demos...
by Christian Brade
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Time for demos...
Snake game Speed game SMS sender Excel with movies Sudoku solver Etc.
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What is a macro
Small computer program, that needs to run within another program.
Collection of instructions for the computer. Automates a task for you.
What you would normally need several clicks for can now be done with one click.
Reduces the risk of errors. Control hole computer, not just MsExcel tasks.
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Recording macros
MS Office has a built-in recorder. You can record anything you can do yourself in
Excel (in theory). You can use the recorder without knowing any
VBA commands. You can edit marcros in VBE (Visual Basic Editor) Macros will be generated to Modules in VBE
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Excercise 1
Start recording Type your name to cell E1 Autowidth column E (doubleclick) Stop recording Check the macro from module1 Clear your name from cell E1 and resize the
column to original width Run the macro
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Excercise 2
Start recording Type your name to cells E1, F2 and G3 Autowidth columns E, F, and G Stop recording Try to shorten the code as much as possible in
the module Clear your name from cells and resize the
columns to original width. Run the macro.
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VBA –programming: Basic elements
If -sentence Loop -structures Event-Run programs Microsoft Visual Basic Help <F1>
’ –to comment lines in a code (apostrophe)
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VBA –programming: Basic elements
If -sentenceIf value = true Then
do thisElse*
do that*End If
Workbook If(value=true;this;that)*Voluntary
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VBA –programming: Basic elements Enhanced If -sentence
If value = 1 ThenMsgBox "1.choise”
ElseIf value = 2 ThenMsgBox "2.choise"
ElseMsgBox ”No choise”
End If
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VBA –programming: Basic elements
Excercise III Code a macro what reads a number from the cell A1
and multiplies it by 2 If the number is smaller than 100. Code the program to Module and name it ExcerciseIII
Sub ExcerciseIII …
End Sub
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Assigning macros to buttons
View – Toolbars – Form – Button Click and draw -> Add macro
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VBA –programming: Basic elements
Excercise IIIb
Assign a button to excercise III
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VBA –programming: Basic elements
Enhanced If –sentence (And and Or)If value = 1 Or value = 2 Then
MsgBox ”Value is 1 or 2”ElseIf value >= 2 And value <=3 Then
MsgBox ”Value is between 2 and 3”Else
MsgBox ”No value”End If
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VBA –programming: Basic elements
Excercise IV Code a macro what reads numbers from the cells A1
and B1. If B1 is greater than A1 change the values. A1 gets the
value of B1 and B1 gets the value of A1. If B1 is not greater than A1, divide the numbers by 2. The macro will be started from a button.
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VBA –programming: Basic elements
Do Loop Whilei = 1
Do Range("A" & i).Value = i i = i + 1Loop While i < 100
What does the loop do?
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VBA –programming: Basic elements
For NextFor i = 1 To 100 Range("A" & i).Value = iNext
What does the loop do? To quit eternal loop <Ctrl+Break>
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VBA –programming: Basic elements
Excercise V Code a macro what types the multiplication table of
number 3 to 100. The macro will be started from a button.
1 * 3 = 32 * 3 = 63 * 3 = 9…100 * 3 = 300
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VBA –programming: Basic elements
Excercise VI Code a macro what types to column N, row 1 one *,
to row 2 ** and finally to row 10 **********. The macro will be started from a button.
******…**********
Visual Basic Editor (VBE) Alt+F11
Place for Event-Run Macros to each Worksheet (Like Worksheet_Change )Place for Event-Run Macros to whole Workbook (Like Workbook_Open)Place for user-defined Macros and function + global variables (Like HelloWorld)
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Creating the Code. What do We Need?
Understand the MS Office object model Access to the Visual Basic Editor VBE Basic programming skills Motivation
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The Object Model. Why bother?
Excel (and the other Office applications) consist of a number of objects
Macro programming is actually just manipulation of these objects
When you understand the basic principle, it’s easier to learn how to program other Office programs
Press a dot after the object and you will the subobjects, properties and methods
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Definition of an object
An object is a named part of a computers memory
It has certain features or properties, like some people have brown hair, others red hair etc.
It has some functionality or methods, like people are able to walk or cars able to drive
Objects can contain other objects
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An example – A box
• Size• Color• Position
Object properties
The object might have a move method.
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The Objects in Excel
The mother object is called an ”Application” An application contains a number of workbooks. These workbooks contain sheets. The sheets contain ranges etc. Application, Workbooks etc. contain many other
objects, properties and methods.
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Excercise VII
Try to find out who is the user of Excel (=application) at the moment.
Find a function ”at the moment” Use MsgBox to show info to the user Start the Macro from button
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Event-run Macros
Normal Macros are run manually Run from Buttons, Shortcuts
Event-run macros will be started automatically. They are started from an event (like Workbook_Open())
Major virus alert! If you open an application with Workbook_Open() Macro, the macro will be run.
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Security levels
Tools – Macros – Security
If your macro doesn’t work in another computer, try to choose Medium level.
Never Low!!!
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Excercise VIII
Code a macro that requires a user’s name and types it to cell A1 when entering to WorkSheet 1 Use InputBox()
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Excercise IX
Code a macro that automatically saves the file when closing it
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Private Sub Workbook_Open()Dim Users(2) As StringDim Found as BooleanFound=FalseUsers(0) = "Christian Brade"Users(1) = "Elvis Presley"Users(2) = "George Bush"For i = 0 To UBound(Users)
If Application.UserName = Users(i) Then Found=TrueEnd If
NextIf Found=False Then
Application.ActiveWorkbook.CloseEnd if
End Sub
Wha
t doe
s th
e co
de d
o?
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Final advice
If you wonder how a certain operation is done, record it and look it from the code.
Place the cursor over a keyword and press F1 for help on that word.
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Thank You!
