About Extracting Attribute Information (VBA/ActiveX)

You can extract attribute information from a drawing using the GetAttributes and GetConstantAttributes methods.

The GetAttributes method returns an array of the attribute references attached to a block, along with their current values. The GetConstantAttributes method returns an array of constant attributes attached to the block or external reference. The attributes returned by this method are the constant attribute definitions, not attribute references.

You do not need template files to extract attribute information, and no attribute information files are created. Simply iterate the array of attribute references, using the TagString and TextString properties of the attribute -reference to examine the attribute information.

The TagString property represents the individual tag for the attribute reference. The TextString property contains the value for the attribute reference.

Get attribute reference information

This example creates a block and then adds an attribute to the block. The block is then inserted into the drawing. The attribute data is then returned and displayed using a message box. The attribute data is then updated for the block reference, and once again the attribute data is returned and displayed. 

Sub Ch10_GettingAttributes()
 ' Create the block
 Dim blockObj As AcadBlock
 Dim insertionPnt(0 To 2) As Double
 insertionPnt(0) = 0
 insertionPnt(1) = 0
 insertionPnt(2) = 0
 Set blockObj = ThisDrawing.Blocks.Add _
 (insertionPnt, "TESTBLOCK")
 
 ' Define the attribute definition
 Dim attributeObj As AcadAttribute
 Dim height As Double
 Dim mode As Long
 Dim prompt As String
 Dim insertionPoint(0 To 2) As Double
 Dim tag As String
 Dim value As String
 height = 1#
 mode = acAttributeModeVerify
 prompt = "Attribute Prompt"
 insertionPoint(0) = 5
 insertionPoint(1) = 5
 insertionPoint(2) = 0
 tag = "Attribute Tag"
 value = "Attribute Value"
 
 ' Create the attribute definition object on the block
 Set attributeObj = blockObj.AddAttribute _
 (height, mode, prompt, _
 insertionPoint, tag, value)
 
 ' Insert the block
 Dim blockRefObj As AcadBlockReference
 insertionPnt(0) = 2
 insertionPnt(1) = 2

 insertionPnt(2) = 0
 Set blockRefObj = ThisDrawing.ModelSpace.InsertBlock _
 (insertionPnt, "TESTBLOCK", 1, 1, 1, 0)
 ZoomAll
 
 ' Get the attributes for the block reference
 Dim varAttributes As Variant
 varAttributes = blockRefObj.GetAttributes
 
 ' Move the attribute tags and values into a
 ' string to be displayed in a Msgbox
 Dim strAttributes As String
 strAttributes = ""
 Dim I As Integer
 For I = LBound(varAttributes) To UBound(varAttributes)
 strAttributes = strAttributes + "  Tag: " + _
 varAttributes(I).TagString + vbCrLf + _
 "   Value: " + varAttributes(I).textString
 Next
 MsgBox "The attributes for blockReference " + _
 blockRefObj.Name & " are: " & vbCrLf _
 & strAttributes
 
 ' Change the value of the attribute
 ' Note: There is no SetAttributes. Once you have the
 ' variant array, you have the objects.
 ' Changing them changes the objects in the drawing.
 varAttributes(0).textString = "NEW VALUE!"
 
 ' Get the attributes again
 Dim newvarAttributes As Variant
 newvarAttributes = blockRefObj.GetAttributes
 
 ' Again, display the tags and values
 strAttributes = ""
 For I = LBound(varAttributes) To UBound(varAttributes)
 strAttributes = strAttributes + "  Tag: " + _
 newvarAttributes(I).TagString + vbCrLf + _
 "   Value: " + newvarAttributes(I).textString
 Next
 MsgBox "The attributes for blockReference " & _
 blockRefObj.Name & " are: " & vbCrLf _
 & strAttributes
End Sub

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