BUG: Unexpected Behavior When FoxPro Application Is Encrypted

• Microsoft FoxPro for MS-DOS, versions 2.5, 2.5a, 2.5b, 2.6, 2.6a

SYMPTOMS

When a FoxPro table (.DBF) file is included in a project and the resulting application (.APP) file is encrypted, you may encounter problems such as a distorted display, a hung computer, or a return to the MS-DOS prompt.

WORKAROUND

To work around this problem, use a third party product such as Cryptor to encrypt the database, or use the techniques outlined in the following article in the Microsoft Knowledge Base:

   ARTICLE-ID: Q115476
   TITLE     : How to Encrypt FoxPro .DBF Files

STATUS

Microsoft has confirmed this to be a problem in the Microsoft products listed at the beginning of this article. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.

MORE INFORMATION

Steps to Reproduce Behavior

1. Start FoxPro for MS-DOS. Use the CUSTOMER.DBF table located in the FPW26\TUTORIAL directory, and create a quick screen. Save the screen as CUSTOMER.SCX.

2. Open the CONTROL3.SCX screen located in the WINDOWS26\TUTORIAL directory.

3. From the File menu, choose Save As to save the screen under a different name (MYCONTROL.SCX). Then close CONTROL3.SCX.

4. From the file menu, choose Open to open MYCONTROL.SCX.

5. Double-click the push buttons and change the Append prompt to Browse. Select the valid code snippet check box to expose the associated code. Then modify the code as shown below.

   DO CASE CASE act2 = 1

         GO TOP
   

   CASE act2 = 2

         SKIP -1
         IF BOF()
            GO TOP
         ENDIF
      CASE act2 = 3
         SKIP 1
         IF EOF()
               GO BOTTOM
         ENDIF
      CASE act2 = 4
         GO BOTTOM
      CASE act2 = 5
      DEFINE WINDOW test FROM 15,0 TO 21,44
      ACTIVATE WINDOW test
      BROWSE IN WINDOW test SAVE NOWAIT WHEN showget()
      CASE act2 = 6
         CLEAR WIND
         CLEAR READ
      ENDCASE
      SHOW GETS
      RETURN 0
   
   

6. Close the valid code snippet. From the system menu, choose Screen. Then choose Screen Layout from the resulting popup. In the Screen Layout dialog, activate the cleanup and procedure snippet. Then type this code:

   PROCEDURE showget SHOW GETS RETURN

   Then close the code snippet, and save the screen with the changes.

7. In the Command window, type the following to start a new project file:

   Create project Test,

8. In the project file, choose Add to include the CUSTOMER.DBF table in the project. Choose Add again to add the CUSTOMER.SCX screen. From the system menu, choose Project. Then select "Set main" to make CUSTOMER.SCX the main program.

9. With CUSTOMER.SCX highlighted in the project, click the edit push button to edit the screen. Then from the edit screen dialog, choose Add to add MYCONTROL.SCX to the screen set. Choose the arrange push button to arrange the two screens side by side. Then save the arrangement, and close the edit screen dialog.

10. From the sys menu, click Project. Then select project info. In the

        project info dialog, select the encrypt check box so the resulting
        TEST.APP file is encrypted. From the project file, choose Build. Then'
        select Build Application to create the TEST.APP file. After completing
        the .APP file, close the project file.
    

11. From the system menu, choose Run. Then choose "Run application," from

        the resulting popup. Select TEST.APP from the group of files.
    

12. When the application is running, press the Next push button to see the

        display update correctly. Then press the Browse button and move through
        the data. You'll see that all records are fine. Press the Bottom push
        button. You'll see a blank screen. try to use any of the push buttons
        again. You will either see no records at all or garbage. After a short
        time the computer may hang.