VB3: HOWTO: Terminate Windows from a Visual Basic Application

The information in this article applies to:

• Standard and Professional Editions of Microsoft Visual Basic for Windows, versions 2.0, 3.0
• Microsoft Visual Basic programming system for Windows, version 1.0

SUMMARY

The Visual Basic SendKeys function cannot be used to close Program Manager in order to terminate Windows. To correctly close Program Manager, you must invoke the ExitWindows API function as shown below.

Many software setup or installation programs are designed to exit Windows, and then restart Windows when the setup or installation is complete. You can make a Visual Basic program automatically exit Windows and then restart Windows by passing the EW_RESTARTWINDOWS value to the ExitWindows API function. The value for the EW_RESTARTWINDOWS constant is &H42.

MORE INFORMATION

You may want to terminate the current Windows session by closing the Program Manager from within a Visual Basic application. You may think that you can activate the Program Manager control menu and send the appropriate key sequences using the Visual Basic SendKeys function. However, this method will not work because after the Close menu item is chosen, a system modal dialog box is opened that prompts you to save changes to Program Manager. A system modal dialog box locks out ALL other programs until it is satisfied. Therefore, the keystroke you send by using the SendKeys function will never arrive in the dialog box.

To correctly close Program Manager, you must use the ExitWindows API function. You can declare this API function in the GLOBAL.BAS module. For example:

1. Start a new project in Visual Basic.

2. Draw a command button on the form.

3. Add the following as a single line to GLOBAL.BAS:

      Declare Function ExitWindows Lib "user" (ByVal wReturnCode as Long,
         ByVal dwReserved as Integer) as Integer
   
   

4. Add the following line of code to the Command button's Click procedure:

   RetVal% = ExitWindows(0,0)

5. Save the file and then run the program.

6. Click the command button.

Steps to Reproduce Behavior

1. Start a New Project in Visual Basic.

2. Draw a Command button on the form.

3. In the Command button Click event procedure, add this code:

   AppActivate("Program Manager") SendKeys "%{ }{DOWN 5}{ENTER 2}", 0 'ALT, SPACE, DOWN 5, ENTER 2

4. Save the file and then run the program.