insert a formula in the block attribute value via vba

[aleair]

Hi everybody,

 

I'm new with autocad. Actually it's my first time I need to write a VBA procedure for autocad. That's the reason why I'm posting this thread.

 

I have blocks with attribute. In one of this attribute I want to insert an expression that calculates a polyline area.

 

Doing it manually works. the expression is:

"%%).Area>%" where 2130001176 is the ObjectID of the specific poly.

 

I tried to insert the expression via vba with this code:

attArr = oBlkRef.GetAttributes

attArr(3).TextString = "%%).Area>%"

 

It doesn't work and the value (corresponding to the poly area) is not calculated. Only "####" is shown as value.

 

Any idea how to insert the expression via VBA?

Edited November 25, 2010 by aleair
error

[BIGAL]

I think you need 2 extra line

 

area ="%%).Area>%"

 

attArr(3).TextString = area

attarr(3).update

 

found this

Sub Example_Area()
   ' This example creates a polyline object and
   ' then uses the area property to find the
   ' area of that polyline.
   
   Dim plineObj As AcadLWPolyline
   Dim points(0 To 5) As Double
   Dim plineArea As Double
   ' Establish the points for the Polyline
   points(0) = 3: points(1) = 7
   points(2) = 9: points(3) = 2
   points(4) = 3: points(5) = 5
   
   ' Create the polyline in modelspace
   Set plineObj = ThisDrawing.ModelSpace.AddLightWeightPolyline(points)
   
   ' Close the polyline and update display of it
   plineObj.Closed = True
   plineObj.Update
   ZoomAll
   
   ' Get the area of the polyline
   plineArea = plineObj.Area
   
   MsgBox "The area of the new Polyline is: " & plineArea, vbInformation, "Area Example"
End Sub

[aleair]

found solution, thanks.

 

Attrib.TextString = "%%).Area \f " & Chr(34) & "%lu2" & Chr(34) & ">%"

where Cstr(id) is poly objectID