Command Line Arguments

A useful facility within VB is the ability to pass arguments into a compiled executable as it launches. These arguments are defined in the command line immediately after the executable. Obviously double clicking the executable provides no facility to pass arguments, however calling your application from the Run option on the Start menu or from within another VB executable allows arguments to be passed as follows:

   myApp.exe -res:800x600 /ADMINACCESS

These arguments have no effect upon the executable, unless they are interrogated using the Command() function, then the applications appearance and functionality can be conditionally determined. Within the initialization code for your application, perhaps in the Sub_Main or Form_Load procedures, these arguments can be used to set attributes of your application. Using Form_Load, with the above command line arguments as an example, the code below could be employed to conditionally initialize your executable:

   Option Explicit
   Public gstrAccessLevel as String

   Private Sub Form_Load()

      Dim strCommandLine as String

      'set string to command line arguments
      strCommandLine = UCase(Command())

      'determine screen res & form size
      If Instr(strCommandLine, "-res:1024x768") > 0 Then
         Me.Width = 12500
         Me.Height = 10000
      ElseIf Instr(strCommandLine, "-res:800x600") > 0 Then
         Me.Width = 10000
         Me.Height = 8000
      Else	'assume 640x480 res
         Me.Width = 8000
         Me.Height = 6400
      End If

      'determine access level
      If Instr(strCommandLine, "/ADMINACCESS") > 0 Then
         gstrAccessLevel = "Administrator"
      Else
         gstrAccessLevel = "StandardUser"
      End If

   Sub End