1. Working with Date Variables (Unit 5)
Visual Basic for Applications

2. Objectives In this unit, you will learn how to:
Reserve a Date variable
Use an assignment statement to assign a value to a Date variable
Assign the VBA Date, Time, and Now functions to a Date variable
Control the appearance of dates and times using the Format function
Perform calculations using Date variables

3. Objectives In this unit, you will learn how to:
Convert a string to a Date data type using the DateValue and TimeValue functions
Refer to the active cell in Excel
Use the Range object’s Offset property in Excel
Preview and print a document in Word
Refer to a control on an Access form
Create a custom toolbar in Access

4. Concept Lesson: Discussing Date Variables
A Date variable is a variable that can store date and time information

5. Reserving a Procedure-level Date Variable
When creating a Date variable, datatype is always the keyword Date
Date variables are automatically initialized to the number 0
The dtm ID indicates that the variable is a Date variable, which can store date and time information
After using the Dim statement to both reserve and initialize a Date variable, you can use an assignment statement to assign a different value to the variable

6. Examples of Dim Statements that Reserve Date Variables
Exhibit 5-1: Some examples of Dim statements that reserve Date variables

7. Using an Assignment Statement
Exhibit 5-2: Some examples of assignment statements
Date literal constant examples:
#January 7, 2003#
#12/31/2002#
#11:05:00 AM#
#7:30:07 PM#)

8. Using VBA’s Date, Time, and Now Functions
VBA’s Date function returns the system date, which is the date maintained by your computer’s internal clock
VBA’s Time function returns the system time, which is the time maintained by your computer’s internal clock
VBA’s Now function returns both the system date and time

9. AssignDisplayDate Procedure
Exhibit 5-3: The AssignDisplayDate procedure

10. Message Box Displayed by the AssignDisplayDate Procedure
Exhibit 5-4: The message box displayed by the AssignDisplayDate procedure

11. Using the Format Function
You can use the VBA Format function to control the appearance of dates and times
The syntax of the Format function:
Format(Expression:=expression, Format:=format)
expression specifies the number, date, time, or string whose appearance you want to format
format is the name of a predefined VBA format

12. Help Screen Showing the VBA Predefined Date/Time Formats
Search for “Format Function” in VBE Help box

13. Examples of Using Format Function (Try the following examples in the Immediate Window)
dtmTime = #17:04:23#
dtmDate = #January 27, 1993#
Print Format(Time, "Long Time")
Print Format(dtmTime, "Medium Time")
Print Format(#8:30:00 PM#, "Short Time")
Print Format(Date, "Long Date")
Print Format(dtmDate, "Medium Date")
Print Format(#March #, "Short Date")
Print Format(dtmTime, "h:m:s")
Print Format(dtmTime, "hh:mm:ss AMPM")
Print Format(dtmDate, "dddd, mmm d yyyy")
Print Format(1,"General Date")

14. Using Dates and Times in Calculations
VBA provides two functions called DateAdd and DateDiff that you can use to perform calculations involving dates and times
The DateAdd function allows you to add a specified time interval to a date or time, and it returns the new date or time

15. Using Dates and Times in Calculations
The DateDiff function allows you to determine the time interval that occurs between two dates
Unlike the DateAdd function, which returns either a future or past date or time, the DateDiff function returns an integer that represents the number of time intervals between two specified dates or times

16. DateAdd and DateDiff Syntax
DateAdd Function
DateAdd(interval, number, date)
DateDiff Function
DateDiff(interval, date1, date2[, firstdayofweek[, firstweekofyear]])

17. Valid Settings for the Interval Argument
The valid settings for the interval argument

18. Examples of the DateAdd Function
Exhibit 5-8: Some examples of the DateAdd function

19. Examples of the DateDiff Function
Exhibit 5-9: Some examples of the DateDiff function

20. Converting Strings to Date or Time
VBA DateValue function or the TimeValue function converts the string to a date or time, respectively
The syntax of the DateValue function is:
DateValue(Date:=stringExpression)
stringExpression represents a valid date ranging from January 1, 100 through December 31, 9999
The syntax of the TimeValue function is:
TimeValue(Time:=stringExpression)
stringExpression represents a valid time ranging from 0:00:00 (12:00:00 AM) through 23:59:59 (11:59:59 PM)

21. Examples of Using the DateValue and TimeValue Functions
Exhibit 5-10: Using DateValue and TimeValue functions

22. Summary
Use Date, Time, and Now functions to return system date and time
Use Format function to control the appearance of date and time
Use DateAdd Function to add a specified time interval to a date or time, and then return the new date or time
Use DateDiff Function to calculate the number of time intervals between two specified dates or times
Use the DateValue function to convert a date string to a Date data type
Use the TimeValue function to convert a time string to a Time data type

23. Excel Lesson Open Excel and select Cell A1 Open Object Browser in VBE
Search for ActiveCell object
What does ActiveCell object represent?
Open immediate window and type:
Application.ActiveCell.value = 108
Application.workbooks(1).Worksheets(1).range(“C5”).select
Print ActiveCell.address
Why do think active cell is a member of application object?

24. The Offset Property
You can use a Range object’s Offset property to refer to a cell located a certain number of rows or columns away from the range itself
The syntax of the Offset property is:
rangeObject.Offset([rowOffset] [,columnOffset])
rowoffset and columnOffset could be positive or negative
Positive rowOffset refers to rows found below the rangeObject
Positive columnOffset refers to columns to the right of the rangeObject

25. Illustration of the Offset Property
Exhibit 5-12: An illustration of the Offset property
Select Cell B5 in Excel
Try the following examples in the Immediate window:
activecell.Offset(-1,-1).Value = "upper left“
activecell.Offset(-1,1).Value = "upper right"
activecell.Offset(1,-1).Value = "lower left“
activecell.Offset(1,1).Value = "lower right”

26. Excel Lesson: Creating the CalcHours Macro Procedure
Open Martin’s workbook
View the code template for the CalcHours procedure

27. Pseudocode for the CalcHours Procedure
Exhibit 5-11: The pseudocode for the CalcHours procedure

28. Word lesson Printing a Document
You can use the Document object’s PrintPreview method to preview a document on the screen before printing it
You can use the Document object’s PrintOut method to print the document on the printer
The syntax of the PrintPreview method is:
documentObject.PrintPreview
The syntax of the PrintOut method is:
documentObject.PrintOut, which prints one copy of the entire documentObject

29. Word Lesson: Using date variables in Word
Open Pat’s document and view the code template for the PrintInvitation procedure

30. Pseudocode for the PrintInvitation Procedure
Exhibit 5-13: The pseudocode for the PrintInvitation procedure

31. Access Lesson: Using date variables in Access
Begin by opening the database and viewing the ProjectsForm form
Then open the Visual Basic Editor and view the code template for the AssignDates procedure

32. Referring to a Control on a Form
Each of the text boxes on a form is considered a Control object in VBA
Each control belongs to the Form object’s Controls collection
You can use the formObject.Controls(controlName) syntax to refer to a control on a form
controlName should be enclosed in quotation marks

33. Pseudocode for the AssignDates Procedure
Exhibit 5-14: The pseudocode for the AssignDates proedure