Handling Control and User Form Events

Events are triggered as a result of the user interacting with controls on a user form along with when predefined actions occur to the user form.

When you open the AutoCAD Objects folder (it may already be open), you see a drawing icon and the name ThisDrawing. When you open the Forms folder (it may already be open), you see a form icon and the name gpDialog, the form you created.

Working with the Project Explorer Window

In the following steps, you learn to work with the Project Explorer window.

  1. In the VBA IDE, one the menu bar, click View menu Project Explorer window or press Ctrl+R to display the Project Explorer window.
  2. On the Project Explorer window, double-click the module you want to edit.

    A code module opens in the Code window, while a user form opens in the Form Editor window.

  3. If you want to edit the code related to the events of a form, select the user form and right-click. Click View Code.
  4. Optionally, click the tools along the top of the Project Explorer window to control the way modules are displayed in the Project Explorer window.

Modifying Existing Code

In the following steps, you update the existing code of the ThisDrawing module.

  1. On the Project window, double-click the ThisDrawing module.
  2. In the Code window, General Declarations section (at the top), update the following code statements: 
    Public trad As Double         ' Updated
Public tspac As Double        ' Updated
Public tsides As Integer      ' Add
Public tshape As String       ' Add

    The variables need to be set as Public so they can be accessed and modified from the code in the user form. The tsides variable will hold the number of sides for the polygon tile and tshape variable will hold the tile shape chosen; either circle or polygon.

  3. Navigate to the gpuser subroutine.
  4. Add an apostrophe to the front of the following lines: 
    trad = ThisDrawing.Utility.GetDistance(sp, "Radius of tiles: ")
tspac = ThisDrawing.Utility.GetDistance(sp, "Spacing between tiles: ")

    Adding an apostrophe turns the code statements into comments, allowing you to keep the code in the project while not allowing it to be executed. The code should now look like the following: 

    ' trad = ThisDrawing.Utility.GetDistance(sp, "Radius of tiles: ")
' tspac = ThisDrawing.Utility.GetDistance(sp, "Spacing between tiles: ")
  5. After the code statements that were commented out in the previous step, add the following code statements: 
    ' Load and display the Garden Path user form
Load gpDialog 
gpDialog.Show
  6. Navigate to the gardenpath macro.
  7. Add the following subroutine before the gardenpath macro; this subroutine draws either circular or polygon tiles: 
    ' Draw the tile with the designated shape
Sub DrawShape(pltile)
  Dim angleSegment As Double
  Dim currentAngle As Double
  Dim angleInRadians As Double
  Dim currentSide As Integer
  Dim varRet As Variant
  Dim aCircle As AcadCircle
  Dim aPolygon As AcadLWPolyline
  ReDim points(1 To tsides * 2) As Double

  ' Branch based on the type of shape to draw
  Select Case tshape
    Case "Circle"
      Set aCircle = ThisDrawing.ModelSpace.AddCircle(pltile, trad)
    Case "Polygon"
      angleSegment = 360 / tsides
      currentAngle = 0

      For currentSide = 0 To (tsides - 1)
        angleInRadians = dtr(currentAngle)
        varRet = ThisDrawing.Utility.PolarPoint(pltile, angleInRadians, trad)
        points((currentSide * 2) + 1) = varRet(0)
        points((currentSide * 2) + 2) = varRet(1)
        currentAngle = currentAngle + angleSegment
      Next currentSide

      Set aPolygon = ThisDrawing.ModelSpace.AddLightWeightPolyline(points)
      aPolygon.Closed = True
  End Select
End Sub
  8. Navigate to the drow subroutine.
  9. Locate the two occurrences of the following code statement in the drow subroutine: 
    Set cir = ThisDrawing.ModelSpace.AddCircle(pltile, trad)
    Comment out the occurrences of the code statement and add the following below the statement to draw the appropriate tile shape: 
    DrawShape pltile       ' Updated
  10. Save the project.

Adding Event Handlers

In the following steps, you add code to the gpDialog user form to define the behavior of the form's controls and what happens when the user form is loaded.

  1. On the Project window, right-click the gpDialog user form and click View Code.
  2. In the Code window, click the Objects drop-down list on the left and select gp_poly.

  3. In the Procedure drop-down list, select Click if it is not selected by default.
  4. In the Private Sub gp_poly_Click procedure that is added, enter the following code statements: 
    gp_tsides.Enabled = True
  ThisDrawing.tshape = "Polygon"

    The code enables the gp_tsides text box and sets the tshape variable of the ThisDrawing module to the text string Polygon.

  5. Add the Click procedure for the gp_circ object and enter the following code statements: 
    gp_tsides.Enabled = False
  ThisDrawing.tshape = "Circle"

    The code disables the gp_tsides text box and sets the tshape variable of the ThisDrawing module to the text string Circle.

  6. Add the Click procedure for the accept object (OK button): 
    Private Sub accept_Click()
  If ThisDrawing.tshape = "Polygon" Then
    ThisDrawing.tsides = CInt(gp_tsides.text)
    If (ThisDrawing.tsides < 3#) Or (ThisDrawing.tsides > 1024#) Then
      MsgBox "Enter a value between 3 and " & _
             "1024 for the number of sides."
      Exit Sub
    End If
  End If

  ThisDrawing.trad = CDbl(gp_trad.text)
  ThisDrawing.tspac = CDbl(gp_tspac.text)

  If ThisDrawing.trad < 0# Then
    MsgBox "Enter a positive value for the radius."
    Exit Sub
  End If

  If (ThisDrawing.tspac < 0#) Then
    MsgBox "Enter a positive value for the spacing."
    Exit Sub
  End If

  GPDialog.Hide
End Sub

    This code tests whether the user choose polygon as the tile shape and specified a valid number of sides for the polygon. The radius and spacing values entered in the text boxes are saved to the variables trad and tspac. Conditional statements are also used to make sure the values of trad and tspac are not 0.

    After the values are obtained and verified, the gpDialog.Hide statement hides the form, passing control back to the subroutine that first called the form.

  7. Add the Click procedure for the cancel object (Cancel button): 
    Private Sub cancel_Click()
  Unload Me
  End
End Sub

    This event handler unloads the form and terminates the entire macro.

  8. Add the Initialize procedure for the UserForm object: 
    Private Sub UserForm_Initialize()
  gp_circ.Value = True
  gp_trad.Text = ".2"
  gp_tspac.Text = ".1"
  gp_tsides.Text = "5"
  gp_tsides.Enabled = False
  ThisDrawing.tsides = 5
End Sub

    This event handler is executed when the user form is loaded the first time in a session.

  9. Save the project.

Testing the Dialog Box

In the following steps, you test the code added to the gpDialog user form.

  1. Click Manage tab Applications panel Run VBA Macro. Find
  2. In the Macros dialog box, select the ThisDrawing.gardenpath macro and click Run.
  3. At the Start point of the path: prompt, enter 2, 2.
  4. At the Endpoint of the path: prompt, enter 9, 8.
  5. At the Half width of the path: prompt, enter 2.
  6. In the Garden Path dialog box, click Polygon.

  7. In the Radius of Tiles text box, enter .5.
  8. In the Space Between Tiles text box, enter .05.
  9. In the Number of Sides text box, enter 8.
  10. Click OK.
Parent topic: Tutorial: Designing a Garden Path (VBA/ActiveX)
Previous topic: Modifying the Properties of the Controls and User Form