Visual Basic for Applications: Object Variables

Craig K. Tyran

Western Washington University

Winter 2009

Agenda

• Object Variables– Naming conventions– Variable declarations– The “Set” statement

• Examples

• In-class Exercise

A. Object Variables1. A variable that represents an object2. Why use object variables???

• Can significantly simplify code• Can make code execute more quickly

3. Example (MS Excel)• Two ways to assign a value to a cell

• Worksheets(“Sheet1”).Range(“B2”).Value = 6 or• rngPayment.Value = 6

• Which statement is simpler to write/read?• Which statement is more efficient to execute?

A. Object Variables (cont.)3. Example (cont.)

• Assigning an object variable• Dim rngPayment as Range• Set rngPayment =

Worksheets(“Sheet1”).Range(“B2”)

• Using an object variable• rngPayment.Value = 6

A. Object Variables (cont.)

4. As indicated in example, object variables need to be declared and assigned

5. Common objects and variable data types in Excel

Object Data Type• Workbook Workbook• Worksheet Worksheet• Range Range

Note: Easy to remember these data types!!!

A. Object Variables (cont.)6. Examples of object variable declaration statements

– Dim wkbSales as Workbook– Dim shtQuarter1 as Worksheet– Dim rngTotal as Range– Quick questions:

• What does “Dim” stand for?• What purpose do the three letter prefixes serve? Naming conventions!!!! Please use them.

– wkb workbook– sht sheet– rng range

A. Object Variables (cont.)7. Examples of object variable “set” statements (and

examples of use)– Dim wkbSales as Workbook Set wkbSales = Workbooks(“Sales.xlsm”)

• e.g., wkbSales.Close– Dim shtQuarter1 as Worksheet Set shtQuarter1 = Workbooks(“Sales.xlsm”). Worksheets(“First

Quarter”)• e.g.,shtQuarter1.Range(“D4”).Formula= “=Sum(“D1:D3”)”

– Dim rngTotals as Range Set rngTotals = Workbooks(“Sales.xlsm”).Worksheets(“First

Quarter”).Range(“A10:E10”)• e.g., rngTotals.ClearContents

A. Object Variables (cont.)8. What is wrong with the following

statements?– Dim shtInventory as Workbook

shtInventory = Workbooks(“Inventory.xlsm”)– Dim Results as Range

Set Results = Workbooks(“Research.docx”). Worksheet(“Findings”).Range(“C12”)

F. In-Class Exercise

• Activities– Create short “macro” programs– Enhance a “What If” DSS– Gain practice with declaring, setting, and

using object variables!!! – Submit exercise via e-mail