MicroStation V8 VBA Programming

The recent release of MicroStation V8 introduces another automation feature, Visual Basic for Applications (VBA). This new implementation of VBA provides rapid development features for designing applications and tools for MicroStation.

Organizations can leverage built-in knowledge of Windows programming to improve the CAD workflow and environment. Casual developers, such as CAD managers, can take advantage of visual interface construction tools to build Windows-like programs quickly.

 

Despite these advantages however, CAD managers may still opt to defer development of more sophisticated applications to professional programmers. Although VBA makes automation easier, there are still problems that require programming skill and experience. Compared to the alternatives, VBA is still easier.

 

MDL, a C programming language, has always had an advantage over MicroStation BASIC Macros for a couple of reasons.

• First, MDL creates elements dynamically, displaying them as they are dragged around the screen.
   
• And second, macros must be started each time you need them, whereas MDL applications are loaded, but run "silent" until a command is requested. However, MDL requires considerable programming expertise, that usually is outside of the average user's scope of knowledge.

MicroStation VBA will run until requested, can handle complex dynamics, so building applications in this easy-to-use programming environment sounds like the way to proceed. But, is ease of programming really the most important aspect of VBA?

 

Well, maybe. But, since MDL, Macros, and don't forget JMDL can already handle automation needs, do we need VBA?

 

In a word, yes. VBA has at least one more advantage. It has the ability to read and write to MicroStation from other applications. For example, a VBA application in Excel can scan the contents of a MicroStation file directly and manipulate the spreadsheet or the design file based on conditions discovered in either file.

 

A manufacturer of spray nozzles may use a spreadsheet to calculate the flow rate required in a main supplying a nozzle array. The spreadsheet could be arranged such that the total flow rate and the pipe main size are calculated based on nozzle model numbers entered into the spreadsheet.

 

An Excel VBA could automatically draw the array and label the drawing with size and flow parameters of the array. The spreadsheet user doesn't need to open the MicroStation drawing or even know how to use MicroStation.



Figure 1: Create Drawing From Excel VBA

 

In the next few pages we will examine the mechanics of the MicroStation VBA process. Using a less complex example we will build an Excel VBA to extract cell names from a design file and lists the names in the spreadsheet.

 

Of course this is a simple example, but it can be extended to create a quantity take off application, or an equipment schedule tool. The possibilities are endless. Imagine linking specification documents to schedules, or comparing vendor drawing data to design data in your MicroStation file.

 

"What? Your vendor drawings are in AutoCAD format not MicroStation?" No problem, AutoCAD implements VBA too, so use MicroStation VBA applications to read data from the AutoCAD files.

 

Teaching Excel VBA about MicroStation

 

Before you can reference MicroStation objects in Excel, VBA needs to know that MicroStation exists. We do this by creating a reference to the DGN 8.0 library using the following steps:

1. Open the VBA editor in the application you want to reference MicroStation from (in Excel, the keyboard shortcut "Alt-F11" will open the editor).
2. Under the Tools pull down menu, choose References. A dialog appears with a list of references for your computer.
   
   Open Excel, press "Alt-F11".
   
   
   
   
   
   Figure 2: Object Library with Small Box Checked
   
   
3. Scroll through this list to find "Bentley MicroStation DGN 8.0 Object Library"
4. Check the small box next to Bentley MicroStation DGN 8.0 Object Library and then click Ok on the

References dialog. Now that there is an object Library we no longer need to create an OLE application object.

 

Some of you may recall that using createObject in VB 6 to edit MicroStation. msApp = createObject("Micro- Station.Application")

 

Creating an Interface

• Add a form to the VBA by choosing the Pull Down Menu "Insert - UserForm".
  
  
  
  
  
  Figure 3: Tools - UserForm Pull Down Menu
   
• Place a Button on the Form and change the Caption to "Get Cell Names".
  
  
  
  Figure 4: Add Button "Get Cell Names" to UserForm1

Tips: Converting Raster to Vector

Can I convert a raster file to a vector file in Microstation J?

 

You need the module MicroStation Descartes or IRAS/B to the job.

 

Building the Command 

• Double-click on the "Get Cell Names" button to open the source code window (see Figure 5).

A template sub routine is automatically created. It will look like this:

Private Sub CommandButton1_Click()

End Sub

Figure 5 Source Code Window

 

Inside this subroutine we will place the script that opens a file, scans the cells in the file, reads the cell names and then places the names into the spreadsheet file. Here's what it will look like.

Private Sub CommandButton1_Click()

      Dim oCell As CellElement
      Dim oScanCriteria As ElementScanCriteria
      Dim dFile As DesignFile
      Dim curCell As Object
      'OPEN THE DESIGN FILE
      dFile = OpenDesignFile
c:\temp\test3d.dgn", True)
      oScanCriteria = New ElementScanCriteria
      ' SET THE SCAN CRITERIA
      oScanCriteria.ExcludeAllTypes()
      oScanCriteria.IncludeType(msdElementTypeCellHeader)
      Dim oScanEnumerator As ElementEnumerator
t oScanEnumerator =
      ActiveModelReference.Scan(oScanCriteria)
      i = 1
      Do While oScanEnumerator.MoveNext
          oCell = oScanEnumerator.Current
          curCell = Worksheets(1).Cells(i, 1)
          curCell.Value = oCell.Name
          i = i + 1
      Loop
      dFile.Close()
  End Sub

After opening the design file, a scan criteria is set. Think of this as a filter. In this case we only want to look for cells. The scan enumerator can be thought of as a list of elements that the search finds, that is executed by the

 

ActiveModelReference.Scan procedure.

 

Once the elements are loaded into the scan enumerator (list). Each element can be processed. In this example we use a "do while" condition to step through each cell found.

 

The code that populates the spreadsheet is contained inside the "do while" and is just two lines that sets the value of the spreadsheet cell (careful, it's just a row-column location in the spreadsheet, and not the same as a

 

MicroStation cell) to the name of the MicroStation cell found by the scanner.

 

Running the Application

 

A Workbook sheets can also contain buttons. In Figure 6, the spreadsheet shows a button labeled "Get Cell Tool"

 

Figure 6 Sheet containing button

 

Tips: Cpwattr.bas

 

Is there a program that will excute the "copy parallel by distance" command, then change that newly copied element to the active level & symbology, all at once?

 

For a Copy Parallel With Active Attributes.program, cpwattr.bas is the BASIC macro.

 

Quickie Tip: What is a SF.DAT file in MicroStation?

 

It is an Bentley internal system file related to licensing. Users need not to know about it.

 

This button also has a code subroutine. The subroutine opens the UserForm1. The code to open the form looks like this:

Private Sub CommandButton1_Click()
    Load(UserForm1)
    UserForm1.Show()
End Sub

To access place buttons on sheets and access the code window for these buttons, click on "Design Mode". This is the triangle icon located on the Controls Toolbox (View>Toolbars).

 

 

Figure 7 Design Mode Toggle on Control Tools Toolbox

 

Once the button has been placed and you add the code to the button, "Exit Design Mode" by clicking on the design mode button in the Control Tools toolbox again.

• Now run the application by clicking on the sheet button. UserForm1 will display.

• Click the Get Cell Names button. Column 1 is populated with cell names.

Final Comments

In designing UserForm1 it would have been appropriate to include a text box to prompt the user for the location of the design file. Further, a browse button helps the user search for a file. Do you think you could add these to your form? Try it.

 

Figure 8 Form with File Text Box, Browse ,Cancel Button

 

VBA opens a new tool kit for office automation. Accessing MicroStation objects in this way can lead to many new applications.

 

And, although you may need to consult a programmer for more sophisticated applications, you will have no problem creating user- friendly applications that take care of everyday problems. You know, like extracting cell names from a design file.