HOWTO: Tell Whether an App Runs in VB Design Environment

The information in this article applies to:

• Standard and Professional Editions of Microsoft Visual Basic Programming System for Windows, version 3.0

SUMMARY

This article describes how a Visual Basic application can determine whether it is running in the design environment or as an executable file. Two ways that Visual Basic does this are explained.

MORE INFORMATION

Visual Basic provides the APP object, which has the property EXENAME. APP.EXENAME reports the name of the executable file when it runs as an executable file. However, in the design environment, APP.EXENAME reports the name of the project. If you use different names for the project and the executable file, then you can use APP.EXENAME to determine whether an application is running in the Visual Basic design environment or as an executable file.

You can also use the Windows API to determine whether an application is running in the Visual Basic Design Environment or as an executable file. When running in the design environment, the application's module name is "VB." However, as an executable file the module name matches the executable file name that is chosen when compiling the application to an executable file from Visual Basic.

Example

You can determine the module name by using the functions GetCurrentTask() and TaskFindHandle() from the Windows API. The following example illustrates how to use the functions to determine whether the application is running in the Visual Basic design environment:

1. Start a new project (Form1 is created by default).

2. Add a new module to the program (MODULE1.BAS by default).

3. Place the following code in the module:

         Type TASKENTRY
            dwSize As Long
            hTask As Integer
            hTaskParent As Integer
            hInst As Integer
            hModule As Integer
            wSS As Integer
            wSP As Integer
            wStackTop As Integer
            wStackMinimum As Integer
            wStackBottom As Integer
            wcEvents As Integer
            hQueue As Integer
            szModule As String * 10
            wPSPOffset As Integer
            hNext As Integer
         End Type
      
         ' The following declare must be entered on a single line
         Declare Function TaskFindHandle Lib "Toolhelp" (lpte As TASKENTRY,
            ByVal hTask As Integer) As Integer
         Declare Function GetCurrentTask Lib "Kernel" () As Integer
      
         Function VBDesignEnvironment () As Integer
            Dim TE As TASKENTRY
            Dim ModuleName As String
            Dim hTask As Integer
            Dim r
      
            hTask = GetCurrentTask()
            TE.dwSize = Len(TE)
            r = TaskFindHandle(TE, hTask)
            ModuleName = Left(TE.szModule, InStr(TE.szModule, Chr(0)) - 1)
      
            If ModuleName = "VB" Then
               VBDesignEnvironment = True
            Else
               VBDesignEnvironment = False
            End If
         End Function
      
   

   
      Sub Form_Load ()
         Me.Show
         If VBDesignEnvironment() Then
            Print "Design Environment"
         Else
            Print "Executable"
         End If
      End Sub