MicroStation^® Configuration Variables and VBA

Configuration Variable Evaluation

Use the ConfigurationVariableValue and the ExpandConfigurationValue methods of the Workspace object to get the value of a CfgVar.

ConfigurationVariableValue obtains the value of a single variable; by default, it evaluates its current value. An argument to ConfigurationVariableValue would be something like "MS_TAGOUTPUT".

ExpandConfigurationValue obtains the value of a compound variable, by which we mean a variable that is defined in terms of other variables. An argument to ExpandConfigurationValue would be something like "$(_USTN_USER)$(_USTN_USERNAME).txt".

Simple Variable Evaluation

Let's take an example. The variable MS_DEF specifies the default folder where MicroStation looks for DGN files. It's value will be set to something like V:\Projects\Project1\DGN\models\ (that's just an example: your CAD directory structure is likely to be quite different). Whenever MicroStation comes across MS_DEF in your workspace, it knows how to expand that variable to the folder path in order to find a given DGN file. An argument to ConfigurationVariableValue would be something like "MS_TAGOUTPUT".

In VBA, you can use ActiveWorkspace.ConfigurationVariableValue to emulate MicroStation …

Sub TraceMsDef ()
  Const strMS_DEF      As String = "MS_DEF"
  Dim folder           As String
  folder = ActiveWorkspace.ConfigurationVariableValue (strMS_DEF, True)
  Debug.Print strMS_DEF & "=" & folder
End Sub

Compound Variable Evaluation

Configuration variables are often defined in terms of other variables. For example, you might have something like this in your configuration file …

PROJECT_ROOT = V:/Projects/
PROJECT_NAME = Project1
MS_DEF = $(PROJECT_ROOT)$(PROJECT_NAME)/DGN/Models/

Use ExpandConfigurationValue to convert this compound variable to a value …

Sub TraceMsDef ()
  Const strMS_DEF      As String = "MS_DEF"
  Dim folder           As String
  folder = ActiveWorkspace.ExpandConfigurationValue (strMS_DEF)
  Debug.Print strMS_DEF & "=" & folder
End Sub

Is a Configuration Variable Valid?

A configuration variable may be defined, but is it valid? Suppose a CfgVar points to some folder, but that folder does not exist. Suppose that we have this scenario, where MS_CELL is pointing to …

V:\Projects\Workspace\Standards\cells\

but the actual directory name is this (note that the final s is omitted) …

V:\Projects\Workspace\Standards\cell\

Is a Configuration Variable Defined?

Often, you want to determine whether a configuration variable is defined or not. Method IsConfigurationVariableDefined of the Workspace is just what you need …

Sub TestCfgVars ()
  TestCfgVar "MS_DEF"
  TestCfgVar "NOT_DEFINED"
End Sub

Sub TestCfgVar (strVarName As String)
  If (IsConfigurationVariableDefined (strVarName)) Then
    Debug.Print "'" & strVarName & "' is defined"
  Else
    Debug.Print "'" & strVarName & "' is not defined"
  End If
End Sub

Environment Variable Evaluation

Operating system environment variables are typically set when you log on to your computer. If your computer is running Windows you can see environment variable settings in the Advanced tab of My Computer, or by using the SET command from a Windows command prompt.

Suppose you want the Windows USERNAME and COMPUTERNAME environment variables. At a Windows command prompt, you can see those names using the SET command. For example …

C:\Documents and Settings\V8.5>set username
USERNAME=V8.5

C:\Documents and Settings\V8.5>set computername
COMPUTERNAME=NOVATRIX

MicroStation evaluates operating system environment variables when it cannot find a MicroStation configuration variable of the same name. You can take advantage of this in VBA …

Sub TraceLogonInfo ()
  Dim computerName        As String
  Dim userName            As String

  Const strCOMPUTERNAME   As String = "COMPUTERNAME"
  Const strUSERNAME       As String = "USERNAME"

  computerName = ActiveWorkspace.ConfigurationVariableValue (strCOMPUTERNAME, True)
  Debug.Print strCOMPUTERNAME & "=" & computerName

  userName = ActiveWorkspace.ConfigurationVariableValue (strUSERNAME, True)
  Debug.Print strUSERNAME & "=" & userName
End Sub