[IronPython] IronPython and COM object useage

Dino Viehland dinov at microsoft.com
Mon Mar 16 17:25:15 CET 2009

Does get_Initialized work?

On 2.0 you might want to run w/ the -X:PreferComInteropAssembly option which will cause us to prefer the interop assembly over using normal COM dispatch.  It'd still probably be interesting to track down the real issue here because that option is gone in 2.6.

From: users-bounces at lists.ironpython.com [mailto:users-bounces at lists.ironpython.com] On Behalf Of Wim De Kimpe
Sent: Monday, March 16, 2009 2:17 AM
To: 'Discussion of IronPython'
Subject: [IronPython] IronPython and COM object useage

Hi all

Not sure if this is the right forum, but I ask my question anyway.

I would like to use IronPython for creating a hardware testing environment, consisting of a "Device Under Test"  and some
measurement equipment like  a lab power supply and voltage meter and things like that.
These instruments come with a library which enables communication  via USB or GPIB.  I have been using them in
VBA for Excel, C# and VB.Net.  Now when I try to do the same in IronPython, I do not seem to get it to work.

I have copied the Interop assembly dll's from my example C# program into a separate directory, and then try to do the same
steps as I do in the example.  Here's the C# example :

using System;
using Agilent.AgilentU2741A.Interop;

namespace Example1
      /// <summary>
      /// Agilent IVI-COM Driver Example Program
      /// Creates a driver object, reads a few Identity interface
      /// properties, and checks the instrument error queue.
      /// May include additional instrument specific functionality.
      /// Runs in simulation mode without an instrument.
      /// Requires a COM reference to the driver's type library.
      /// </summary>
      public class App
            public static void Main(string[] args)
                  Agilent.AgilentU2741A.Interop.AgilentU2741A driver = null;

                        // Create driver instance
                        driver = new Agilent.AgilentU2741A.Interop.AgilentU2741AClass();

                        // Setup VISA resource descriptor.  Ignored if Simulate=true
                        string resourceDesc = "USB0::2391::18712::SN-4567890::0::INSTR";
                        // Setup IVI-defined initialization options
                        string standardInitOptions =
                              "QueryInstrStatus=true, Simulate=true";
                        // Setup driver-specific initialization options
                        string driverSetupOptions =
                              "DriverSetup= Model=, Trace=false";

                        driver.Initialize(resourceDesc, false, true, standardInitOptions + "," + driverSetupOptions);
                        Console.WriteLine("  Driver Initialized");

                        // IIviDriverIdentity properties - Initialize required
                        string instModel = driver.Identity.InstrumentModel;
                        Console.WriteLine("InstrumentModel: {0}", instModel);

                        string instFirmwareRevision = driver.Identity.InstrumentFirmwareRevision;
                        Console.WriteLine("InstrumentFirmwareRevision: {0}", instFirmwareRevision);

                        string instManufacturer = driver.Identity.InstrumentManufacturer;
                        Console.WriteLine("InstrumentManufacturer: {0}\n", instManufacturer);

                        // TODO: Exercise driver methods and properties

                        // Check instrument for errors
                        int errorNum = -1;
                        string errorMsg = null;
                        while (errorNum != 0)
                              driver.Utility.ErrorQuery(ref errorNum, ref errorMsg);
                              Console.WriteLine("ErrorQuery: {0}, {1}", errorNum, errorMsg);
                  catch (Exception ex)
                        if (driver != null && driver.Initialized)
                              // Close driver
                              Console.WriteLine("  Driver Closed");

                  Console.WriteLine("\nDone - Press Enter to Exit");

Here is what I try to do in Ironpython :

>>> import sys
>>> import clr
>>> clr.AddReferenceToFile("Agilent.AgilentU2741A.Interop.dll")
>>> from Agilent.AgilentU2741A.Interop import *
>>> a = AgilentU2741AClass()
>>> a
<Agilent.AgilentU2741A.Interop.AgilentU2741AClass object at 0x000000000000002B>
>>> dir(a)
['AC', 'ACCurrent', 'ACVoltage', 'Abort', 'ActualRange', 'Advanced', 'Alpha', 'A
pertureTime', 'ApertureTimeUnits', 'AutoRange', 'AutoZero', 'Cache', 'Calibratio
n', 'Clear', 'ClearInterchangeWarnings', 'Close', 'Code', 'Configure', 'Configur
eBandwidth', 'ConfigureServiceRequest', 'ConfigureSynchronization', 'Continuity'
, 'Count', 'CreateObjRef', 'DCCurrent', 'DCVoltage', 'Delay', 'Description', 'Di
ode', 'DirectIO', 'Disable', 'DriverOperation', 'DriverSetup', 'Equals', 'ErrorQ
uery', 'FResistance', 'Fetch', 'FetchMultiPoint', 'FixedRefJunction', 'Frequency
', 'FrequencyMax', 'FrequencyMin', 'Function', 'GeographicalAddress', 'GetHashCo
de', 'GetLifetimeService', 'GetNextCoercionRecord', 'GetNextInterchangeWarning',
 'GetType', 'GroupCapabilities', 'IAgilentU2741AACVoltage_AutoRange', 'IAgilentU
2741AACVoltage_Configure', 'IAgilentU2741AACVoltage_Measure', 'IAgilentU2741AACV
oltage_Range', 'IAgilentU2741AContinuity_Configure', 'IAgilentU2741AContinuity_M
easure', 'IAgilentU2741ADCCurrent_AutoRange', 'IAgilentU2741ADCCurrent_AutoZero'
, 'IAgilentU2741ADCCurrent_Range', 'IAgilentU2741ADCVoltage_AutoRange', 'IAgilen
tU2741ADCVoltage_AutoZero', 'IAgilentU2741ADCVoltage_Configure', 'IAgilentU2741A
DCVoltage_Measure', 'IAgilentU2741ADCVoltage_NPLC', 'IAgilentU2741ADCVoltage_Ran
ge', 'IAgilentU2741ADCVoltage_Resolution', 'IAgilentU2741ADiode_Configure', 'IAg
ilentU2741ADiode_Measure', 'IAgilentU2741AFResistance_AutoRange', 'IAgilentU2741
AFResistance_AutoZero', 'IAgilentU2741AFResistance_Configure', 'IAgilentU2741AFR
esistance_Measure', 'IAgilentU2741AFResistance_NPLC', 'IAgilentU2741AFResistance
_Range', 'IAgilentU2741AFResistance_Resolution', 'IAgilentU2741AFrequency_Config
ure', 'IAgilentU2741AFrequency_Measure', 'IAgilentU2741AResistance_AutoRange', '
IAgilentU2741AResistance_AutoZero', 'IAgilentU2741AResistance_Configure', 'IAgil
entU2741AResistance_Measure', 'IAgilentU2741AResistance_NPLC', 'IAgilentU2741ARe
sistance_Range', 'IAgilentU2741AResistance_Resolution', 'IIviComponentIdentity_D
escription', 'IIviComponentIdentity_Revision', 'IIviComponentIdentity_Vendor', '
IIviDmmAdvanced_ActualRange', 'IIviDmmAdvanced_ApertureTime', 'IIviDmmAdvanced_A
pertureTimeUnits', 'IIviDmmAdvanced_AutoZero', 'IIviDmmAdvanced_PowerlineFrequen
cy', 'IIviDmmMeasurement_Abort', 'IIviDmmMeasurement_Fetch', 'IIviDmmMeasurement
_Initiate', 'IIviDmmMeasurement_IsOverRange', 'IIviDmmMeasurement_Read', 'IIviDm
mMeasurement_SendSoftwareTrigger', 'IIviDmmMultiPoint_Count', 'IIviDmmRTD_Config
ure', 'IIviDmmRTD_Resistance', 'IIviDmmThermistor_Resistance', 'IIviDmmTrigger_S
lope', 'IIviDmmTrigger_Source', 'IIviDmm_Advanced', 'IIviDmm_Close', 'IIviDmm_Dr
iverOperation', 'IIviDmm_Frequency', 'IIviDmm_Function', 'IIviDmm_Identity', 'II
viDmm_Initialize', 'IIviDmm_Initialized', 'IIviDmm_Measurement', 'IIviDmm_Range'
, 'IIviDmm_Resolution', 'IIviDmm_Temperature', 'IIviDmm_Trigger', 'IIviDmm_Utili
ty', 'IIviDriver_Close', 'IIviDriver_DriverOperation', 'IIviDriver_Identity', 'I
IviDriver_Initialize', 'IIviDriver_Initialized', 'IIviDriver_Utility', 'Identifi
er', 'Identity', 'Initialize', 'InitializeLifetimeService', 'Initialized', 'Init
iate', 'InstrumentFirmwareRevision', 'InstrumentManufacturer', 'InstrumentModel'
, 'InterchangeCheck', 'InvalidateAllAttributes', 'IoResourceDescriptor', 'IsOver
Range', 'LockObject', 'LogicalName', 'Measure', 'Measurement', 'MeasurementCompl
ete', 'MemberwiseClone', 'Message', 'MultiPoint', 'NPLC', 'PerformADCCalibration
', 'PerformCalibration', 'PowerlineFrequency', 'Preset', 'QueryInstrumentStatus'
, 'RTD', 'Range', 'RangeCheck', 'Read', 'ReadMultiPoint', 'ReadingUnits', 'Recor
dCoercions', 'RefJunctionType', 'ReferenceEquals', 'Register', 'Reset', 'ResetCa
librationCode', 'ResetInterchangeCheck', 'ResetWithDefaults', 'Resistance', 'Res
olution', 'Revision', 'SampleCount', 'SampleInterval', 'SampleTrigger', 'Securit
yEnable', 'SecurityState', 'SelfTest', 'SendSoftwareTrigger', 'SerialNumber', 'S
erialPoll', 'Simulate', 'Slope', 'Source', 'SpecificationMajorVersion', 'Specifi
cationMinorVersion', 'Status', 'StoreCalibrationConstants', 'SupportedInstrument
Models', 'SynchronizationBusLine', 'SynchronizationState', 'System', 'Temperatur
e', 'Thermistor', 'Thermocouple', 'TimeoutMilliseconds', 'ToString', 'Transducer
Type', 'Trigger', 'Type', 'UnitTemperature', 'UnlockObject', 'Utility', 'Value',
 'Vendor', 'VoltageRange', 'WaitForOperationComplete', '__class__', '__delattr__
', '__doc__', '__getattribute__', '__hash__', '__init__', '__new__', '__reduce__
', '__reduce_ex__', '__repr__', '__setattr__', '__str__']
' object has no attribute 'Load'
>>> a.Initialized()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'GenericComObject' object has no attribute 'Initialized'

At this point I was expected to just get : FALSE.
Also when I try to call the Initialize method (which seems to be imported correctly), I get the same error : unknown attribute.
When I try to step through the available methods,  I do not get any of the interesting ones, only the 'generic' ones.
Also I have checked the Interop assembly using  IL DASM, and there also I get the full list, so I think the interop assembly is ok.

What do I do wrong? Is this because it is a  COM object ?  The IronPython tutorial is not very elaborate on what is actually happening during
the exercice, so I am running a bit out of ideas here...



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