Adding blocks with fieldcode attributes using VBA

I am trying to use VB/VBA to insert a block that has attributes contaaining
fieldcodes. If I use the AutoCAD insret command, everything works as
expected, however, using the method ThisDrawing.ModelSpace.InsertBlock will
simply insert the block without the fieldcodes.

Is there a new method to invoke when using fieldcodes? Or am I missing
something simpler?

regards,


--
John W. Janzen


Autodesk Authorized Consultant
Autodesk Registered Developer

Cadmin
www.cadmin.com
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Can you send me a drawing with a block with
attributes that contains field codes? I'd
like to have a look at it. Have you tried to
to insert the field code by including the
field expression in the value passed to the
attributeReference's TextString property?

 

Hey Tony,

Actually, it's ANY AutoCAD block with a field code. I used file name to
test. Inserting a a field code like in Text and Mtext is simple, but I can't
see where the field codes are stored within an attribute value of a
block...otherwise, I don't know what the user has entered! Simply stated, if
the user creates a block with attributes containing Field Codes, the AutoCAD
Insert command works fine, it's just the VBA methods that are a mystery.

Not sure if I explained it any better.

John

 

Well, I just tried it (defined an attribute with the
drawing filename field), and inserted it using the
InsertBlock method (from LISP, not VBA) and it works
here. I set the attribute definition to PRESET, not
sure if that has anything to do with it.

What did find interesting, is that if you saveas to
another filename, the fields update, but if you then
issue UNDO 1, the field reverts to the previous
filename. Not sure that makes sense.

 

Hmmm...just adjusted my blocks wto use PRESET, however, still doesn't work
with VBA.

This is the routine I am using...

Sub test()
Dim ms As IAcadModelSpace2
Set ms = ThisDrawing.ModelSpace
Dim pt
pt = ThisDrawing.Utility.GetPoint(, "Insertion point: ")
ms.InsertBlock pt, "block", 1, 1, 1, 0
End Sub


John

 

Is the field code inserted into your attribute
definition?

 

yes, it is...like I said, if I use the acad insert, it works great, but if I
use the VBA method, it doesn't.

John

 

Well, I've boiled it down to extension dictionaries. Fieldcode data is
attached to the attributes references as extension dictionaries. These are
created automatically when using the acad insert command, but are missing if
the InsertBlock method is used.

The attributes within the block definition contain the extension
dictionaries, but not in the same format. Trying to map them now and apply
manually...I'll let you know what I come up with.

John

 

Hi John,
Only attributes with mode acAttributeModeConstant seem to work. Are you too
seeing the same?

Ravi

Sub test()
Dim pt(2) As Double
Dim bk As IAcadBlock2
Set bk = ThisDrawing.Blocks.Add(pt, "ModeNormal")
bk.AddCircle pt, 1
bk.AddAttribute 0.5, acAttributeModeNormal, "Prompt", pt, "tag",
"Normal: %<\AcVar Filename \f ""%fn7"">%"
Call ThisDrawing.ModelSpace.InsertBlock(pt, "ModeNormal", 1, 1, 1, 0)

Set bk = ThisDrawing.Blocks.Add(pt, "ModeConstant")
bk.AddCircle pt, 3
bk.AddAttribute 0.5, acAttributeModeConstant, "Prompt", pt, "tag",
"Constant: %<\AcVar Filename \f ""%fn7"">%"
pt(0) = 10: pt(1) = 10
Call ThisDrawing.ModelSpace.InsertBlock(pt, "ModeConstant", 1, 1, 1, 0)

pt(0) = 0: pt(1) = 0
Set bk = ThisDrawing.Blocks.Add(pt, "ModePreset")
bk.AddCircle pt, 5
bk.AddAttribute 0.5, acAttributeModePreset, "Prompt", pt, "tag",
"Preset: %<\AcVar Filename \f ""%fn7"">%"
pt(0) = 20: pt(1) = 20
Call ThisDrawing.ModelSpace.InsertBlock(pt, "ModePreset", 1, 1, 1, 0)

pt(0) = 0: pt(1) = 0
Set bk = ThisDrawing.Blocks.Add(pt, "ModeVerify")
bk.AddCircle pt, 7
bk.AddAttribute 0.5, acAttributeModeVerify, "Prompt", pt, "tag",
"Verify: %<\AcVar Filename \f ""%fn7"">%"
pt(0) = 30: pt(1) = 30
Call ThisDrawing.ModelSpace.InsertBlock(pt, "ModeVerify", 1, 1, 1, 0)

AcadApplication.Update
ZoomExtents
End Sub

 

You're correct about what you're seeing. I just confirmed it.

There are a few other things I noticed as well (see below).

To insert the field into the attribute text, you don't have
to fiddle with extension dictionaries (and in fact, you shouldn't
do that because it requires dealing with custom objects like
the FIELD object).

You only have to set the TextString property of the
AcadAttributeReference to the field expression, which
for the DWG filename is:

%<\AcVar Filename \f \"%fn6\">%

The above gives you just the filename without case
conversion and path. Also note that if you code this
as a literal string in VB, you'll have to deal with
the embedded double quotes.

I noticed that when I did this using Visual LISP, AutoCAD
loaded these:

Loading AEC Base...
Loading AEC Project Base...
Loading AEC Base UI...

My guess is that this is where the field evaluators are.

Another thing I also noticed, is that Autodesk neglected
to provide any support for fields to the editors in the
Properties Palette (not good, because it looks like there
is no field at all, but rather just regular text).

 

Usually when we refer to 'attributes', we mean variable
block attributes, not constant attributes (which are
essentially like text entities in the block definition).