Extract Attribute Information

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.

For more information on extracting attribute information, see “Extract Data from Block Attributes” in the User's Guide.

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