Public Variables May Be Lost When You Copy a Worksheet

MORE INFORMATION

Microsoft provides programming examples for illustration only, without warranty either expressed or implied. This includes, but is not limited to, the implied warranties of merchantability or fitness for a particular purpose. This article assumes that you are familiar with the programming language that is being demonstrated and with the tools that are used to create and to debug procedures. Microsoft support engineers can help explain the functionality of a particular procedure, but they will not modify these examples to provide added functionality or construct procedures to meet your specific requirements. In Visual Basic for Applications, you can create a public variable by adding the word "Public" to a variable declaration at the top of a module.

Example:

   Public X As Integer 
   Public Y As String

   Sub Test()
       ' <Your code goes here.>
   End Sub
				

Normally, public variables retain their values until you close the workbook in which they are contained. However, if the conditions listed in the "Cause" section of this article are true, the public variables may unexpectedly lose their values. The following steps demonstrate this problem.

Steps to Reproduce Behavior

1. In Microsoft Excel, create a new workbook.
2. On the Tools menu, point to Macro, and then click Visual Basic Editor. On the Insert menu, click Module.
3. Type the following code into the new module:

           Public X As Integer
         Public Y As String
   
         Sub CopySheet()
             Worksheets("Sheet1").Copy After:=Worksheets(Worksheets.Count)
         End Sub
   
         Sub SetVars()
             X = 5
             Y = "Hello!"
         End Sub
   
         Sub ShowVars()
             MsgBox X
             MsgBox Y
         End Sub
   						

4. On the Tools menu, click Options. Click the Editor tab. Select the Require Variable Declaration check box, and then click OK.
5. On the File menu, click "Close and Return to Microsoft Excel."
6. On the Tools menu, point to Macro, and then click Macros. Select SetVars, and then click Run.
   
   The variables now contain the values 5 and "Hello!"
7. On the Tools menu, point to Macro, and then click Macros. Select ShowVars, and then click Run. Two message boxes appear containing the values 5 and "Hello!"
8. On the Tools menu, point to Macro, and then click Macros. Select CopySheet, and then click Run.
   
   Or, click Move Or Copy Sheet on the Edit menu. Select the Create A Copy check box. In the list, click "(move to end)", and then click OK.
   
   The worksheet Sheet1 is copied; the new worksheet, "Sheet1 (2)," appears at the end of the workbook.
9. On the Tools menu, point to Macro, and then click Macros. Select ShowVars, and then click Run.
   
   As before, two message boxes appear. However, the first message box contains the value zero (0), and the second message box is empty. This occurs because the act of copying the worksheet reinitialized the public variables.
   
   If you repeat these steps, but leave the Require Variable Declaration check box cleared in step 4, the public variables will correctly retain their values.