Читать книгу Excel Macros For Dummies - Dick Kusleika - Страница 45

Before you can do anything meaningful, you must have some VBA code in the VBA module. You can get VBA code into a VBA module in three ways:

 Use the Excel macro recorder to record your actions and convert them to VBA code.

 Enter the code directly.

 Copy the code from one module and paste it into another.

Chapter 1 shows you how to create code by using the Excel macro recorder. However, not all tasks can be translated to VBA by recording a macro. You often have to enter your code directly into the module. Entering code directly basically means either typing the code yourself or copying and pasting code you have found somewhere else.

Entering and editing text in a VBA module works as you might expect. You can select, copy, cut, paste, and do other things to the text.

A single line of VBA code can be as long as you like. However, you may want to use the line-continuation character to break up lengthy lines of code. To continue a single line of code (also known as a statement) from one line to the next, end the first line with a space followed by an underscore (_). Then continue the statement on the next line. Here’s an example of a single statement split into three lines:

Selection.Sort Key1:=Range("A1"), _ Order1:=xlAscending, Header:=xlGuess, _ Orientation:=xlTopToBottom

This statement would perform exactly the same way if it were entered in a single line (with no line-continuation characters). Notice that the second and third lines of this statement are indented. Indenting is optional, but it helps clarify the fact that these lines are not separate statements.

The VBE has multiple levels of undo and redo. If you delete a statement that you shouldn’t have, click the Undo button on the Standard toolbar (or press Ctrl+Z) until the statement appears again. After undoing, you can click the Redo button to perform the changes you’ve undone.

Ready to enter some real, live code? Try the following steps:

1 Create a new workbook in Excel.

2 Press Alt+F11 to open the VBE.

3 Click the new workbook’s name in the Project Explorer.

4 Choose Insert ⇒ Module to insert a VBA module into the project.

5 Type the following code into the module: Sub GuessName() Dim Msg as String Dim Ans As Long Msg = "Is your name " & Application.UserName & "?" Ans = MsgBox(Msg, vbYesNo) If Ans = vbNo Then MsgBox "Oh, never mind." If Ans = vbYes Then MsgBox "I must be clairvoyant!" End Sub

6 Make sure the cursor is located anywhere within the text you typed and press F5 to execute the procedure.

The VBE has its own set of shortcut keys you can use to quickly run a command using your keyboard. F5 is a shortcut for Run ⇒ Run Sub/UserForm.

When you enter the code listed in Step 5, you might notice that the VBE makes some adjustments to the text you enter. For example, after you type the Sub statement, the VBE automatically inserts the End Sub statement. And if you omit the space before or after an equal sign, the VBE inserts the space for you. Also, the VBE changes the color and capitalization of some text. This is all perfectly normal. It’s just the VBE’s way of keeping things neat and readable.

If you followed the previous steps, you just created a VBA Sub procedure, also known as a macro. When you press F5, Excel executes the code and follows the instructions. In other words, Excel evaluates each statement and does what you told it to do. You can execute this macro any number of times — although it tends to lose its appeal after a few dozen executions.

This simple macro uses the following concepts:

 Defining a Sub procedure (the first line)

 Declaring variables (the Dim statements)

 Assigning values to variables (Msg and Ans)

 Concatenating (joining) a string (using the & operator)

 Using a built-in VBA function (MsgBox)

 Using built-in VBA constants (vbYesNo, vbNo, and vbYes)

 Using an If-Then construct (twice)

 Ending a Sub procedure (the last line)

As mentioned previously, you can copy and paste code into a VBA module. For example, a Sub or Function procedure that you write for one project might also be useful in another project. Instead of reentering the code, you can open the module and use the normal copy-and-paste procedures (Ctrl+C to copy and Ctrl+V to paste). After pasting it into a VBA module, you can modify the code as necessary.