VBA Programming

Session #2

Things to Review Variables Procedures: Subs & Functions If…Then For…Next

Variables Just like in math, variables:

Have a name Have a value Value can be changed

Examples: x = 1 : debug.print x x = 2 : debug.print x

Procedures Subroutines (Subs)

Can do things but not return values. Subs without arguments can be called from the

Excel macro toolbar. Functions

Functions return values in VBA with the form: FunctionName = SomeValue

Functions can be inserted into Excel sheets from the Insert|Function menu.

If…Then If…Then has two basic forms:

StatementIf (x = 1) Then Debug.Print "Yes"

Code BlockIf (x = 1) Then y = 1Else y = -1End If

For…Next Loops through a range of values and executes

the statements in the block.

For x = 1 To 10 Debug.Print xNext

1 2 3 4 5 6 7 Etc.

New Stuff

VBA Variable Types The most commonly used VBA types are:

Boolean (True or False) Numeric Types: Integer, Double, Currency Date String Variant (holds almost anything) Object Types: Ranges, Worksheets, etc.

Objects A combination of code and data that can

be treated as a unit, for example, a control, form, or application component. Each object is defined by a class. (MS)

Examples: Workbooks Worksheets Charts Ranges

Declaring Variables Declaring means:

Telling VBA that you are going to use it Defining the variable's type

Declare variables using the Dim statement Dim MyName as String Dim MyBirthday as Date Dim BigMoney as Currency Dim wks as Worksheet

Assigning Values to Variables Most variables can simple be assigned like

this: X = 5 MyName = "Bob"

Objects need to be assigned using Set Set MyDataSheet = ActiveSheet Set MyChart = ActiveChart

Forgot to set?

Range Object Represents a cell, a row, a column, a selection of

cells containing one or more contiguous blocks of cells, or a 3-D range. (MS)

Understanding Ranges

Ranges: Writing CodeSub SimplestHello() Range("A1") = "Hello" Range("A2", "B4") = "Goodbye"End Sub

Ranges: Using a Range VariableSub HelloRange() Dim a1 As Range Set a1 = Range("A1") a1 = "Hello world!"End Sub

Offsets: If only there was just "A1"

Combining it all... Data Table

The Macro Recorder: Part II

Specific -> Generic Instead of...

Range("A1") Sheets("Sheet1") Charts("Chart1")

Use Selection or ActiveCell ActiveSheet ActiveChart

Collection Object Most of the VBA objects you use are parts

of collections. For example: Charts: a collection of Chart objects Worksheets: a collection of Worksheet objects

Collections have the following: Count: number of items in the collection Add: add an item Item: get the value of an item Remove: delete item

Collection: Example

Sub AddWorksheet() Dim wks As Worksheet Set wks = Worksheets.Add MsgBox "Added: " + wks.NameEnd Sub

Looping Through Collections Collections are handy to use because we

can easily look at each item in the collection using a "For Each" loop.

For example:

Sub ListWorksheets() Dim wks As Worksheet For Each wks In ActiveWorkbook.Worksheets MsgBox wks.Name NextEnd Sub

Collections: Exercise