Writing Word Macros, Second Edition

Constants

The VBA language has two types of constants. A literal constant (also called a constant or literal) is a specific value, such as a number, date, or text string, that does not change and that is used exactly as written. Note that string constants are enclosed in double quotation marks, as in:

	"Donna Smith"

and date constants are enclosed between number signs, as in:

	#1/1/96#

For instance, the following code stores a date in the variable called dt:

	Dim dt As Date
	dt = #1/2/97#

The second type of constant, a symbolic constant (also sometimes referred to simply as a constant), is another name for a literal constant.

To define or declare a symbolic constant in a program, use the Const keyword:

	Const InvoicePath = "d:\Invoices\"

In this case, Word will replace every instance of InvoicePath in our code with the string “d:\Invoices\”. Thus, InvoicePath is a constant, since it never changes value, but it is not a literal constant, since it is not used as written.

The virtue of using symbolic constants is that, if we decide later to change “d:\ Invoices\” to “d:\OldInvoices\”, you need to change only the definition of InvoicePath:

	Const InvoicePath = "d:\OldInvoices\"

rather than search through the entire program for every occurrence of the phrase “d:\Invoices\”!

Note that it is generally good programming practice to declare any symbolic constants at the beginning of the procedure in which they are used (or in the Declarations section of a code module). This improves readability and simplifies ...