OUTLINE
Excel – Basic Elements Using Macros Excel VBA Basics Excel VBA Advanced
MODULES & PROCEDURES
Module – collection of logically related procedures grouped together
Procedure – a group of ordered statements enclosed by Sub and End Sub
Function – the same as a procedure, but also returns some value and is closed between Function and End Function key words
PROCEDURE & FUNCTION EXAMPLES
Sub ShowTime() Range("C1") = Now()
End Sub
Function sumNo(x, y) sumNo = x + y
End Function
The procedure places the current time inside cell C1
The function returns sum of two input numbers, whose values are in the
parameter variables x & y
CALLING PROCEDURES VS. CALLING FUNCTIONS
Sub z(a) MsgBox a
End Sub
Sub x() Call z("ABC")
End Sub
Sub y() z "ABC“
End Sub
Sub ShowSum() MsgBox _ Module1.sumNo(3,5)
End Sub
Function sumNo(x, y) sumNo = x + y
End Function
If there are few sumNo functions, the full name of the function is needed
PASSING ARGUMENTS BY VALUE OR BY REFERENCE
Passing arguments by reference – Is the VBA default Means, if any changes happened to the argument
variables, they will be preserved after the function/procedure finishes
Passing arguments by value – Is possible in VBA (by explicit definition) Means, the pre-calling state of the argument
variables will be preserved after the procedure/function finishes
ARGUMENTS BY REF/BY VAL. EXAMPLES
Sub TestPassing1() Dim y As Integer y = 50 AddNo1 y MsgBox y AddNo2 y MsgBox y
End Sub
Sub AddNo1(ByRef x As Integer) x = x + 10
End Sub
Sub AddNo2(x As Integer)x = x + 10
End Sub
public Sub TestPassing2() Dim y As Integer y = 50 AddNo3 y MsgBox y
End Sub
private Sub AddNo3(ByVal x _ As Integer) x = x + 10
End Sub
FUNCTIONS/PROCEDURE SCOPE
Use public to allow any module to call the function/procedure
Use private to make limited access to the function/procedure (only from the owning module)
VBA VARIABLES
A variable is used to store temporary information within a Procedure, Module…
A variable name Must start with letter and can’t contain spaces and
special characters (such as “&”, “%”, “\”) Can’t be any excel keyword (“if”, “while”…) Can’t have identical name to any existing class
(“Wroksheet”, “Workbook”…)
VBA DATA TYPE
Byte – positive integer numbers (0:255) Integer – integers (-32,768 : 32,767) Long – 4-byte integer Currency – for fixed-point calculations Single – 2-byte floating-point numbers
VBA DATA TYPE
Double – double-precision floating-point numbers
Date – used to store dates and times as real numbers.
String – contains a sequence of characters
THE VARIABLES ADVANTAGE BY EXAMPLE
Sub NoVariable()Range("A1").Value = _
Range("B2").Value Range("A2").Value = _
Range("B2").Value * 2Range("A3").Value = _
Range("B2").Value * 4 Range("B2").Value = _
Range("B2").Value * 5 End Sub
Sub WithVariable() Dim _ iValue as Integer iValue = _ Range("B2").Value Range("A1").Value = _
iValue Range("A2").Value = _
iValue * 2 Range("A3").Value = _
iValue * 4 Range("B2").Value = _
iValue * 5 End Sub
In VB the end of statement is in the end of line.To write the same statement in few lines use “_” at the end of line!
USING VARIABLES
Declaring Variables Format: Dim varibaleName AS dataType Examples:
Dim myText As String Dim myNum As Integer Dim myObj As Range
The default value of any numeric variable is zero any string variable – “” (empty string) an Object variable – is nothing (still the declaration will
store space for the object!!!)
VARIANT “DATA TYPE”
In VB you don’t have to declare variable before its usage Then, VB will by itself declare such variable as “Variant”
You can also declare variable as “Variant” Dim myVar as Variant
Variant – means that the variable may contain any data type The price is very high!!! – any time VB access
such variable, it will spend time on “deciding” what is its “current” type!
VARIABLES ASSIGNMENT
To assign a value to a Numeric or String type Variable, you simply use your Variable name, followed by the equals sign (=) and then the String or Numeric
To assign an Object to an Object type variable you must use the key word "Set"
VARIABLES ASSIGNMENT – CONT.
Sub ParseValue() Dim sWord as String Dim iNumber as Integer Dim rCell as Range Set rCell = Range("A1") sWord = Range("A1").Text iNumber = Range("A1").Value
End Sub
VBA VARIABLES SCOPE & LIFECYCLE
The scope & lifecycle of a variable defines the code where the variable can be accessed and time when the stored data is kept inside the variable
Procedure-Level Variables defined inside procedures Can be accessed only inside the procedure and keep their data
until the End statement of the procedure Module-Level
Defined in the top of a Module Any procedure inside the Module can access the variable The variable retains the values unless the Workbook closes
Project-Level, Workbook Level, or Public Module-Level Defined as “Public” in the top of a Module Can be accesses by any procedure in any module The variable retains the values unless the Workbook closes
VBA VARIABLES SCOPE & LIFECYCLE – CONT.
Sub scopeExample()Dim x as Integerx = 5
End Sub Dim y as Integer‘all the module procedures are here…
Public z as Integer‘all the module procedures are here…
Procedure level variables
Module level variables
Project level variables
BASIC EXCEL CLASSES
Workbook: the class represents an Excel file
Worksheet: represents a single worksheet
Sheet: represents a single worksheet or chartsheet
Cell: represents a single cell
VBA ENTITIES BY EXAMPLE
A current Worksheet
A Range C4:D7A Cell
A CurrentWorkbook
EXCEL CONTAINERS
Workbooks: a collection of objects of class “Workbook”
Worksheets: a collection of objects of class “Worksheet”
Sheets: a collection of Sheet objects Range: a range of objects of class Cell
REFERENCING THE OBJECTS - EXAMPLES
Sub Test1() Worksheets("Sheet1").Range("A10", "B12")
= "Hello“ Worksheets(1).Range("A13,B14") = "World!"End Sub
This will take the whole
square between the two cells
The range of two cells
Two equal ways to refer Sheet1
THE OUTPUTWhich Workbook
wasUsed?
WHAT DOES THIS PROCEDURE DO?
Sub ShowWorkSheets() Dim mySheet As Worksheet For Each mySheet In Worksheets MsgBox mySheet.Name Next mySheet
End Sub
THE OUTPUT!How many times
the user will click on the
button?
REFERENCING CELLS
Cells indexing format: Cells(row, column), where both row and column
are given as integers (starting from 1) Cells(index) – see the next slide
Following expressions are equivalent and refer to the cell A1 in the currently active sheet: ActiveSheet.Range.Cells(1,1) Range.Cells(1,1) Cells(1,1)
REFERENCING CELLS WITH OFFSET
Range(“B1:F5”).Cells(12) = “XYZ”
See how we calculate cell 12In the given range!
REFERENCING CELLS WITH OFFSET – CONT.
ActiveCell.Offset(4, 5) = 1
This is the currently active cell
The assignment
result
FEW METHODS/PROPERTIES OF EXCEL CLASSES
Workbooks.Close – closes the active workbook
Workbooks.Count – returns the number of currently open workbooks
Range(“A1”) is the same as Range(“A1”).Value Worksheets(1).Column(“A:B”).AutoFit Worksheets(1).Range(“A1:A10”).Sort_ Workbooks.Open fileName:=“Hello.xls”,
password:=“kukuriku”
DEFINING AND ASSIGNING A NEW OBJECT OF TYPE RANGE
Dim myRange as RangeSet myRange = Range(“A1:A10”)
VBA ARRAYS
Suppose, we want to keep a collection of all the books that we loan,
Or we want to keep lists of tasks for all the days of the week The naïve solution is to keep a lot of
variables Another solution is to create array keeping
the whole collection together
DECLARING OBJECT OF TYPE ARRAY
Dim LoanBooks(3)
LoanBooks(1) = “Winnie The Pooh”LoanBooks(2) = “Adventures of Huckleberry
Finn”LoanBook(3) = “Frankenstein”
The array declaration.The size must be
defined here!
MULTIDIMENSIONAL ARRAYS
Dim WeekTasks(7,2)
WeekTasks(1,1) = “To buy milk”WeekTasks(7,1) = “To dance”…
MsgBox WeekTasks(1,1) & ” ” & WeekTasks(1,2) _ & vbCrLf & WeekTasks(2,1)…
What will the code print?
RESIZING THE ARRAYS
There are two ways to resize the existing array: ReDim LoanBooks(7) – will erase the old
values ReDim Preserve LoanBooks(7) – will
preserve values in indexes 1-3
UPPER & LOWER INDEX BOUNDS OF AN ARRAY
Dim A(1 To 100, 0 To 3, -3 To 4) UBound(A, 1) – will return “100” UBound(A, 2) – will return “3” UBound(A, 3) – will return “4” LBound(A, 1) – will return “1” LBound(A, 2) – will return “0” LBound(A, 3) – will return “-3”
Write code calculating the size of each one of the sub-arrays
VBA CONTROL STRUCTURES - IF
If Age >= 18 Then Status = "Adult" End If If Age >=18
Then Status = “Adult”Vote = “Yes”
ElseStatus = “Child”Vote = “No”
End If
VBA CONTROL STRUCTURES - IF
If Age >= 18 Then MsgBox "You can vote"ElseIf Age >=22 and Age < 62
Then MsgBox “You can drive”End If
VBA CONTROL STRUCTURES – SELECT Select Case Grade Case Is >= 90 LetterGrade = "A" Case Is >= 80 LetterGrade = "B" Case Is >= 70 LetterGrade = "C" Case Is >= 60 LetterGrade = "D" Case Else LetterGrade = “E"End Select
VBA CONTROL STRUCTURES – LOOPS
For i = 10 to 1 Step -2 Cells(i, 1) = “AB”
Next i
i = 1Do While i =< 10
Cells(i, 1) = i i = i + 1
Loop
i = 1 Do Cells(i, 1) = i i = i + 1 Loop While i < 11
TEST YOURSELF! WHAT DOES THE PROCEDURE DO?
Sub CellsExample() For i = 1 To 5 For j = 1 To 5 Cells(i, j) = "Row " & i & " Col " & j Next j Next iEnd Sub