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: Statement If (x = 1) Then Debug.Print "Yes" Code Block If (x = 1) Then y = 1 Else y = -1 End If

For…Next  Loops through a range of values and executes the statements in the block. For x = 1 To 10 Debug.Print x Next 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 Code Sub SimplestHello() Range("A1") = "Hello" Range("A2", "B4") = "Goodbye" End Sub

Ranges: Using a Range Variable Sub 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.Name End 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 Next End Sub

Collections: Exercise