Entity Creation Order

Is there a way of determining which of two entities was created last.

I am attaching xdata to blocks and am trying to get around the problem of
the User copying a block and therefore creating duplicate xdata.

I hope to prevent this by running my own audit command when a drawing is
opened and if duplicate xdata is found moving the last created block to an
error layer

Thanks is advance
--
Regards
Tom Roberts
__________________________
MechWest Design & Drafting
Perth, Western Australia

 

compare their handles

 

I insert a block its handle=9C
I insert another instance of the same block and its handle = C7

If you can explain to me the logic behind how handles are assigned then
comparing their handles may be a valid option.

 

Hi Tom,

There are probably hexadecimal numbers.

9C = 9*16 + 12 in decimal terms.
C7= 12*16 + 7

1 =1
2=2
....
A = 10
B = 11
--
F = 15
10 = 16
etc

You should be able to find comparison operations with the numbers in that
format.

--


Laurie Comerford
CADApps
www.cadapps.com.au

 

Hi Tom

Convert Hex to Decimal with this function:

Code:

Public Function Hex2Dec(HexVal As String) As Variant

Dim PosCnt As Integer
Dim StrLen As Integer
Dim TmpVal As Integer
Dim CurDig As Variant
Dim RetVal As Variant

PosCnt = 1
StrLen = Len(HexVal)

Do
CurDig = UCase(Mid(HexVal, PosCnt, 1))
TmpVal = IIf(Asc(CurDig) > 64, Asc(CurDig) - 55, CVar(CurDig))
RetVal = RetVal + (TmpVal * (16 ^ (StrLen - PosCnt)))
PosCnt = PosCnt + 1
Loop Until PosCnt > StrLen

Hex2Dec = CDec(RetVal)

End Function

Cheers

 

Hi Tom,
Handles get assigned in order of object creation.
They never change from dwg session to dwg session in a given dwg.
They are never duplicated,(as far as I understand)
So they appear to be safe references to track objects.
Here's what I came up with thanks to Juerg's generous offer of the Hex2Dec
function

'test sub to demonstrate usage of comparing handles
'to try this, draw two lines
'put each one on a different layer
'run the sub and pick the two lines

'using Juerg Menzi's Generously donated function of Hex2Dec


'test sub
Public Sub testGetYoungerEntity()
Dim oline As AcadLine
Dim oline2 As AcadLine
Dim oYounger As AcadEntity

Set oline = adcxGetEnt("Pick Line")
Set oline2 = adcxGetEnt("Pick Line")
Set oYounger = YoungerEntity(oline, oline2)

Debug.Print "Younger entity is on layer: " & oYounger.Layer
msgbox "Younger entity is on layer: " & oYounger.Layer

Set oline = Nothing
Set oline2 = Nothing
Set oYounger = Nothing

End Sub



'quicky selection wrapper to simplify look of main code block - not done yet
Public Function ADCXGetEnt(strPrmpt As String) As AcadEntity
Dim rtnEnt As AcadEntity
Dim vpt As Variant

'error code goes here
ThisDrawing.Utility.GetEntity rtnEnt, vpt, strPrmpt
If Not rtnEnt Is Nothing Then
Set ADCXGetEnt = rtnEnt
Else
MsgBox "GetEntity failed", vbCritical, "ADCX ERROR", , "ADCXGetEnt Function"

End If

End Function

'funny little comparison function
Public Function YoungerEntity(ByRef oEnt1 As AcadEntity, ByRef oEnt2 As
AcadEntity) As AcadEntity
If Hex2Dec(GetHandle(oEnt1)) > Hex2Dec(GetHandle(oEnt2)) Then
Set YoungerEntity = oEnt1
Else
Set YoungerEntity = oEnt2
End If

End Function


'simple wrapper
Public Function GetHandle(oent As AcadEntity) As String
GetHandle = oent.Handle
End Function



'Generously provided by: Juerg Menzi
'Thanks Juerg!
Public Function Hex2Dec(HexVal As String) As Variant

Dim PosCnt As Integer
Dim StrLen As Integer
Dim TmpVal As Integer
Dim CurDig As Variant
Dim RetVal As Variant

PosCnt = 1
StrLen = Len(HexVal)

Do
CurDig = UCase(Mid(HexVal, PosCnt, 1))
TmpVal = IIf(Asc(CurDig) > 64, Asc(CurDig) - 55, CVar(CurDig))
RetVal = RetVal + (TmpVal * (16 ^ (StrLen - PosCnt)))
PosCnt = PosCnt + 1
Loop Until PosCnt > StrLen

Hex2Dec = CDec(RetVal)

End Function

Hope some of that helps
Mark

 

Hi Laurie,
Thanks for that explanation,
I'm sure i've read about hex before but that's the clearest explanation I've
seen.
And even with that clarity, it took me a minute to figure out the 10=16 but
then i see
1 * 16 + 0
cool

Thanks,
Mark

 

Hi,

Try this. A Hex number can be indicated by preceding it with &H

Sub fred()
Dim x As Long
Dim y aAs Long
y = &HABA
x = 1135566
If x > y Then
MsgBox Hex(x) & " x>y " & Hex(y)
Else
MsgBox Hex(y) & " y >x " & Hex(x)
End Sub

--


Laurie Comerford
CADApps
www.cadapps.com.au

 

Hi Laurie

Thanks for enlighten me...

Didn't recognize the 'Hex' function in VB. My sample is a translation from
LISP to VB. In this connection I got another maybe useful insight:
- Handles are by type String
- Hex needs a number and has limited range
Solution:
cDec("&H" + "FFFFFF")
16777215

Cheers

 

Forget my unqualified babble...8-(

'Hex' is the correct solution.

Cheers

 

Hi Mark

Laurie is right. Hex is the more elegant way to compare handles.
Therefore your solution can look like this (Hex2Dec -> garbage):

'funny little comparison function
Public Function YoungerEntity(ByRef oEnt1 As AcadEntity, _
ByRef oEnt2 As AcadEntity) As AcadEntity
If Hex(GetHandle(oEnt1)) > Hex(GetHandle(oEnt2)) Then
Set YoungerEntity = oEnt1
Else
Set YoungerEntity = oEnt2
End If

End Function

'simple wrapper
Public Function GetHandle(oent As AcadEntity) As String
GetHandle = "&H" + oent.Handle
End Function

Cheers

 

Hi Tom, Mark and Jürg,

Tom, thanks for the question and to the rest of us, this has been a great
discussion and example of the symbiosis which can arise in the NGs.


--


Laurie Comerford
CADApps
www.cadapps.com.au

<snip>

 

Wonderful stuff guys

I pop up a question and go away for the week-end only to return to one of
the more interesting threads I have read for a while, and a solution to my
problem to boot.

Thank-you

--
Regards
Tom Roberts
__________________________
MechWest Design & Drafting
Perth, Western Australia