Retrieve output parameters from an AutoCAD API method in python

问题

I'm trying to retrieve 2 output Arrays from an XRecord in AutoCAD 2016 using python 2.7, with comtypes imported, the first array is an array of integers (DXF Group Codes) and the second array is an array of variants (the values of XRecord).

The opposite way of what this question seeks to

The method of interest is GetXRecordData, which (according to AutoCAD's documentation) if successful returns None, and only accepts 2 output arguments.

when I try to retrieve it with code like

DxfGrCd = []
vals = []
an_XRecord.GetXRecordData(DxfGrCd, vals)

and see the values of DxfGrCd and vals I found no change happened to them, both of them still equal to [], the same is also with

DxfGrCd = {}
vals = {}
anXRecord.GetXRecordData(DxfGrCd, vals)

also no change is applied on them, both of them still equal to {}, even though dictionaries and lists are mutable.

Is there any way to deal with that kind of methods in python?

回答1:

Well, I haven't figured out any way to do so from python, however, since the data stored in XRecords are just numbers and strings (in my application), stored in the XRecord as variants, I've used MS Excel as a middle man to pass me data.

Note: All numbers I've got were retrieved but as floats.

And all strings were retrieved but their type is unicode. (you can convert them to string easily with the built-in function str())

Here's how I've done that.

---

First: Creation of The Facilitator Workbook (Our Middle Man)

1-Normally as a regular windows user, open Excel, then open Visual Basic Editor, one way to do that is to go to Developer tab and click on Visual Basic Editor.

2-From the Editor, insert a module (one way is from the menu bar: insert>Module), then left-double click on its default name and type "mod_facilitate", then hit Enter.

3-Left-double click on its icon at the project viewer.

4- A window will appear, copy the following code to it.

Sub getxrecord()
'get running AutoCAD object
Dim mycad As AcadApplication, mydoc As AcadDocument, filepath As String
Set mycad = GetObject(, "AutoCAD.Application.20")
'get the selected drawing, provided from python code
With Sheet1
    filepath = .Range(.Cells(1, 1), .Cells(1, 1)).Value
End With

Dim iCount As Integer, i As Integer, j As Integer, CompName As String
iCount = mycad.Documents.Count
For i = 0 To iCount - 1
    CompName = mycad.Documents.Item(i).FullName
    If CompName Like filepath Then
        j = i
        Exit For
    End If
Next i
Set mydoc = mycad.Documents.Item(j)
Dim name2 As String

'get the object from its provided handle

With Sheet1
    handler = .Range(.Cells(2, 1), .Cells(2, 1)).Value
End With
Dim myXRecord As AcadXRecord
Set myXRecord = mydoc.HandleToObject(handler)

Dim DxfGrcd As Variant, Val As Variant
DxfGrcd = Array()
Val = Array()
myXRecord.GetXRecordData DxfGrcd, Val

Dim UB As Integer
UB = UBound(DxfGrcd)
For i = 0 To UB
    With Sheet1
        .Range(.Cells((i + 1), 2), .Cells((i + 1), 2)).Value = DxfGrcd(i)
        .Range(.Cells((i + 1), 3), .Cells((i + 1), 3)).Value = Val(i)
    End With
Next i

End Sub

5- From Tools>References Select these reference names, leaving the others at their previous states

AcSmComponents20 1.0 Type Library
AutoCAD 2016 Type Library
CAO 1.0 Type Library

Then click on OK, then hit Ctrl+s to save.

6- Save the file and name it "facilitator", save it within the same directory of your python file. Save it of type Excel Macro-Enabled Workbook (has the extension .xlsm)

7- At your python file, define the function to retrieve XRecord's data as following, I'll tell what are its arguments for:

def XRecord_return(namefile,handle,size):
    xl.Range["A1"].Value[xlRangeValueDefault] = namefile
    xl.Range["A2"].Value[xlRangeValueDefault] = handle
    xl.Application.Run("facilitator.xlsm!mod_facilitate.getxrecord")

    dxfgrcd = []
    vals = []
    for i in range(0,size):
        CellB = 'B' + str(i+1)
        CellC = 'C' + str(i+1)
        dxfgrcd.append(xl.Range[CellB].Value[xlRangeValueDefault])
        vals.append(xl.Range[CellC].Value[xlRangeValueDefault])

    return dxfgrcd,vals

Second: What to Insure

Note: All the following steps must be written before the definition of XRecord_return

1- AutoCAD must be instantiated from python using a line like autocad = CreateObject("AutoCAD.Application.20",dynamic=True) or autocad = comtypes.client.CreateObject("AutoCAD.Application.20",dynamic=True) depending on the scope of importing and importing form [ import comtypes.client or from comtypes.client import CreateObject ], here, importing scope is the python file's module scope.

2-instantiate Excel using xl = CreateObject("Excel.Application") and open the facilitator file with

xlpath = os.getcwd()
xlpath += '\\facilitator.xlsm'
xl = CreateObject("Excel.Application")
from comtypes.gen.Excel import xlRangeValueDefault
xlwb = xl.Workbooks.Open(Filename=xlpath,ReadOnly=0)

3- You have to know how many elements are stored in the XRecord (excluding the number of associated DXF group codes), this number of elements is what you'll supply to XRecord_return as its size argument.

e.g. An XRecord that stores 3.0 "abc" 5 and have correspondent DXF group codes 1 2 3 is of size 3, not 6.

Third: Supplying Data to The Facilitator Workbook

We need only its first worksheet, you must provide the following data:-

1- The drawing's full path/directory to cell "A1".

To get the drawing's full path if you have its Document object you can get it from the property FullName. This value is what you'll supply to XRecord_return as its namefile argument.

To assign, for instance: xl.Range["A1"].Values[xlRangeValueDefault] = filepath

2-The XRecord's handle value to cell "A2", you can get it from the property Handle of the XRecord. This value is what you'll supply to XRecord_return as its 'handle' argument.

To assign, for instance: xl.Range["A1"].Values[xlRangeValueDefault] = handlevalue

3- After that, wherever you need to get the XRecords data, call the XRecord_return function, like

DxfGrCd,vals = XRecord_return(filepath,handlevalue,size_of_XRecord)

The outputs are lists that contain the correspondent data.

Last, But not Least

When you finish using Excel for retrieving data from as many XRecords as you need, close the facilitator workbook using xlwb.Close(SaveChanges=0)

来源：https://stackoverflow.com/questions/45764375/retrieve-output-parameters-from-an-autocad-api-method-in-python